diff --git a/README.md b/README.md
index f766676..8560e98 100644
--- a/README.md
+++ b/README.md
@@ -66,6 +66,10 @@ local observation = env:start()
 
 **Note that the API is under development and may be subject to change**
 
+### rlenvs.envs
+
+A table of all possible environments implemented in rlenvs.
+
 ### observation = env:start([opts])
 
 Starts a new episode in the environment and returns the first `observation`. May take `opts`.
@@ -74,7 +78,7 @@ Starts a new episode in the environment and returns the first `observation`. May
 
 Performs a step in the environment using `action` (which may be a list - see below), and returns the `reward`, the `observation` of the state transitioned to, and a `terminal` flag. Optionally provides `actionTaken`, if the environment provides supervision in the form of the actual action taken by the agent in spite of the provided action.
 
-### stateSpec = env:getStateSpec()
+### stateSpec = env:getStateSpace()
 
 Returns a state specification as a list with 3 elements:
 
@@ -86,11 +90,11 @@ Returns a state specification as a list with 3 elements:
 
 If several states are returned, `stateSpec` is itself a list of state specifications. Ranges may use `nil` if unknown.
 
-### actionSpec = env:getActionSpec()
+### actionSpec = env:getActionSpace()
 
 Returns an action specification, with the same structure as used for state specifications.
 
-### minReward, maxReward = env:getRewardSpec()
+### minReward, maxReward = env:getRewardSpace()
 
 Returns the minimum and maximum rewards produced by the environment. Values may be `nil` if unknown.
 
diff --git a/experiment.lua b/experiment.lua
index a184662..89e37d3 100644
--- a/experiment.lua
+++ b/experiment.lua
@@ -1,38 +1,32 @@
-local image = require 'image'
-local Catch = require 'rlenvs/Catch'
-
--- Detect QT for image display
-local qt = pcall(require, 'qt')
+require 'rlenvs'
+local Catch = require('rlenvs.Catch')
 
 -- Initialise and start environment
-local env = Catch({level = 2})
-local stateSpec = env:getStateSpec()
-local actionSpec = env:getActionSpec()
+local env = Catch({level = 2, render = true, zoom = 10})
+local actionSpace = env:getActionSpace()
 local observation = env:start()
 
-local reward, terminal
+local reward, terminal = 0, false
 local episodes, totalReward = 0, 0
-local nSteps = 1000 * (stateSpec[2][2] - 1) -- Run for 1000 episodes
+local nEpisodes = 1000
 
 -- Display
-local window = qt and image.display({image=observation, zoom=10})
+env:render()
 
-for i = 1, nSteps do
-  -- Pick random action and execute it
-  local action = torch.random(actionSpec[3][1], actionSpec[3][2])
-  reward, observation, terminal = env:step(action)
-  totalReward = totalReward + reward
+for i = 1, nEpisodes do
+  while not terminal do
+    -- Pick random action and execute it
+    local action = torch.random(0, actionSpace['n'] - 1)
+    reward, observation, terminal = env:step(action)
+    totalReward = totalReward + reward
 
-  -- Display
-  if qt then
-    image.display({image=observation, zoom=10, win=window})
+    -- Display
+    env:render()
   end
 
-  -- If game finished, start again
-  if terminal then
-    episodes = episodes + 1
-    observation = env:start()
-  end
+  episodes = episodes + 1
+  observation = env:start()
+  terminal = false
 end
 print('Episodes: ' .. episodes)
 print('Total Reward: ' .. totalReward)
diff --git a/rlenvs/Acrobot.lua b/rlenvs/Acrobot.lua
index 38af8ff..368e114 100644
--- a/rlenvs/Acrobot.lua
+++ b/rlenvs/Acrobot.lua
@@ -1,11 +1,14 @@
 local classic = require 'classic'
 
 local Acrobot, super = classic.class('Acrobot', Env)
+Acrobot.timeStepLimit = 500
 
 -- Constructor
 function Acrobot:_init(opts)
   opts = opts or {}
-  
+  opts.timeStepLimit = Acrobot.timeStepLimit
+  super._init(self, opts)
+
   -- Constants
   self.g = opts.g or 9.8
   self.m1 = opts.m1 or 1 -- Mass of link 1
@@ -21,27 +24,40 @@ function Acrobot:_init(opts)
 end
 
 -- 4 states returned, of type 'real', of dimensionality 1, with differing ranges
-function Acrobot:getStateSpec()
-  return {
-    {'real', 1, {-math.pi, math.pi}}, -- Joint 1 angle
-    {'real', 1, {-math.pi, math.pi}}, -- Joint 2 angle
-    {'real', 1, {-4*math.pi, 4*math.pi}}, -- Joint 1 angular velocity
-    {'real', 1, {-9*math.pi, 9*math.pi}} -- Joint 2 angular velocity
+function Acrobot:getStateSpace()
+  local state = {}
+  state['name'] = 'Box'
+  state['shape'] = {4}
+  state['low'] = {
+    -math.pi, -- Joint 1 angle
+    -math.pi, -- Joint 2 angle
+    -4*math.pi, -- Joint 1 angular velocity
+    -9*math.pi -- Joint 2 angular velocity
+  }
+  state['high'] = {
+    math.pi, -- Joint 1 angle
+    math.pi, -- Joint 2 angle
+    4*math.pi, -- Joint 1 angular velocity
+    9*math.pi -- Joint 2 angular velocity
   }
+  return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, with second torque joint in {-1, 0, 1}
-function Acrobot:getActionSpec()
-  return {'int', 1, {-1, 1}}
+function Acrobot:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = 3
+  return action
 end
 
 -- Min and max reward
-function Acrobot:getRewardSpec()
+function Acrobot:getRewardSpace()
   return -1, 0
 end
 
 -- Resets the cart
-function Acrobot:start()
+function Acrobot:_start()
   -- Reset angles and velocities
   self.q1 = 0 -- Joint 1 angle
   self.q2 = 0 -- Joint 2 angle
@@ -52,7 +68,8 @@ function Acrobot:start()
 end
 
 -- Swings the pole via torque on second joint
-function Acrobot:step(action)
+function Acrobot:_step(action)
+  action = action - 1 -- rescale the action
   local reward = -1
   local terminal = false
 
diff --git a/rlenvs/Atari.lua b/rlenvs/Atari.lua
index 83e1ea8..23cb39c 100644
--- a/rlenvs/Atari.lua
+++ b/rlenvs/Atari.lua
@@ -6,11 +6,15 @@ if not hasALEWrap then
 end
 
 local Atari, super = classic.class('Atari', Env)
+Atari.timeStepLimit = 100000
 
 -- Constructor
 function Atari:_init(opts)
   -- Create ALEWrap options from opts
   opts = opts or {}
+  opts.timeStepLimit = Atari.timeStepLimit
+  super._init(self, opts)
+
   if opts.lifeLossTerminal == nil then
     opts.lifeLossTerminal = true
   end
@@ -44,13 +48,25 @@ function Atari:_init(opts)
 end
 
 -- 1 state returned, of type 'real', of dimensionality 3 x 210 x 160, between 0 and 1
-function Atari:getStateSpec()
-  return {'real', {3, 210, 160}, {0, 1}}
+function Atari:getStateSpace()
+  local state = {}
+  state['name'] = 'Box'
+  state['shape'] = {3, 210, 160}
+  state['low'] = {
+    0
+  }
+  state['high'] = {
+    1
+  }
+  return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, between 1 and 18 (max)
-function Atari:getActionSpec()
-  return {'int', 1, {1, #self.actions}}
+function Atari:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = #self.actions
+  return action
 end
 
 -- RGB screen of height 210 and width 160
@@ -59,12 +75,12 @@ function Atari:getDisplaySpec()
 end
 
 -- Min and max reward (unknown)
-function Atari:getRewardSpec()
+function Atari:getRewardSpace()
   return nil, nil
 end
 
 -- Starts a new game, possibly with a random number of no-ops
-function Atari:start()
+function Atari:_start()
   local screen, reward, terminal
   
   if self.gameEnv._random_starts > 0 then
@@ -77,7 +93,7 @@ function Atari:start()
 end
 
 -- Steps in a game
-function Atari:step(action)
+function Atari:_step(action)
   -- Map action index to action for game
   action = self.actions[action]
 
diff --git a/rlenvs/Blackjack.lua b/rlenvs/Blackjack.lua
index 7d436c4..b174455 100644
--- a/rlenvs/Blackjack.lua
+++ b/rlenvs/Blackjack.lua
@@ -7,31 +7,45 @@ local Blackjack, super = classic.class('Blackjack', Env)
 function Blackjack:_init(opts)
   opts = opts or {}
 
+  super._init(self, opts)
+
   -- Create number-only suit
   self.suit = torch.Tensor({2, 3, 4, 5, 6, 7, 8, 9, 10, 10, 10, 10, 11})
 end
 
 -- 2 states returned, of type 'int', of dimensionality 1, for the player sum, dealer's showing card, and player-usable ace
-function Blackjack:getStateSpec()
-  return {
-    {'int', 1, {2, 20}},
-    {'int', 1, {1, 10}},
-    {'int', 1, {0, 1}}
+function Blackjack:getStateSpace()
+  local state = {}
+  state['name'] = 'Box'
+  state['shape'] = {3}
+  state['low'] = {
+    2,
+    1,
+    0
+  }
+  state['high'] = {
+    20,
+    10,
+    1
   }
+  return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, either stand or hit
-function Blackjack:getActionSpec()
-  return {'int', 1, {0, 1}}
+function Blackjack:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = 2
+  return action
 end
 
 -- Min and max reward
-function Blackjack:getRewardSpec()
+function Blackjack:getRewardSpace()
   return -1, 1
 end
 
 -- Draw 2 cards for player and dealer
-function Blackjack:start()
+function Blackjack:_start()
   -- Shuffle deck
   self.deck = torch.cat({self.suit, self.suit, self.suit, self.suit}, 1):index(1, torch.randperm(52):long())
 
@@ -51,7 +65,7 @@ function Blackjack:start()
 end
 
 -- Player stands or hits
-function Blackjack:step(action)
+function Blackjack:_step(action)
   local reward = 0
   local terminal = false
 
diff --git a/rlenvs/CartPole.lua b/rlenvs/CartPole.lua
index 5b1e49b..cb5b584 100644
--- a/rlenvs/CartPole.lua
+++ b/rlenvs/CartPole.lua
@@ -1,11 +1,14 @@
 local classic = require 'classic'
 
 local CartPole, super = classic.class('CartPole', Env)
+CartPole.timeStepLimit = 200
 
 -- Constructor
 function CartPole:_init(opts)
   opts = opts or {}
-  
+  opts.timeStepLimit = CartPole.timeStepLimit
+  super._init(self, opts)
+
   -- Constants
   self.gravity = opts.gravity or 9.8
   self.cartMass = opts.cartMass or 1.0
@@ -19,27 +22,40 @@ function CartPole:_init(opts)
 end
 
 -- 4 states returned, of type 'real', of dimensionality 1, with differing ranges
-function CartPole:getStateSpec()
-  return {
-    {'real', 1, {-2.4, 2.4}}, -- Cart position
-    {'real', 1, {nil, nil}}, -- Cart velocity
-    {'real', 1, {math.rad(-12), math.rad(12)}}, -- Pole angle
-    {'real', 1, {nil, nil}} -- Pole angular velocity
+function CartPole:getStateSpace()
+  local state = {}
+  state['name'] = 'Box'
+  state['shape'] = {4}
+  state['low'] = {
+    -2.4, -- Cart position
+    math.huge, -- Cart velocity
+    math.rad(-12), -- Pole angle
+    math.huge -- Pole angular velocity
+  }
+  state['high'] = {
+    2.4, -- Cart position
+    math.huge, -- Cart velocity
+    math.rad(12), -- Pole angle
+    math.huge -- Pole angular velocity
   }
+  return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, between 0 and 1 (left, right)
-function CartPole:getActionSpec()
-  return {'int', 1, {0, 1}}
+function CartPole:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = 2
+  return action
 end
 
 -- Min and max reward
-function CartPole:getRewardSpec()
+function CartPole:getRewardSpace()
   return -1, 0
 end
 
 -- Resets the cart
-function CartPole:start()
+function CartPole:_start()
   -- Reset position, angle and velocities
   self.x = 0 -- Cart position (m)
   self.xDot = 0 -- Cart velocity
@@ -50,7 +66,7 @@ function CartPole:start()
 end
 
 -- Drives the cart
-function CartPole:step(action)
+function CartPole:_step(action)
   -- Calculate acceleration
   local force = action == 1 and self.forceMagnitude or -self.forceMagnitude
   local cosTheta = math.cos(self.theta)
@@ -66,10 +82,10 @@ function CartPole:step(action)
   self.thetaDot = self.thetaDot + self.tau * thetaDotDot
 
   -- Check failure (if cart reaches sides of track/pole tips too much)
-  local reward = 0
+  local reward = 1
   local terminal = false
   if self.x < -2.4 or self.x > 2.4 or self.theta < math.rad(-12) or self.theta > math.rad(12) then
-    reward = -1
+    reward = 0
     terminal = true
   end
 
diff --git a/rlenvs/Catch.lua b/rlenvs/Catch.lua
index 40ba990..16b9b94 100644
--- a/rlenvs/Catch.lua
+++ b/rlenvs/Catch.lua
@@ -5,6 +5,7 @@ local Catch, super = classic.class('Catch', Env)
 -- Constructor
 function Catch:_init(opts)
   opts = opts or {}
+  super._init(self, opts)
 
   -- Difficulty level
   self.level = opts.level or 2
@@ -28,13 +29,25 @@ function Catch:_init(opts)
 end
 
 -- 1 state returned, of type 'int', of dimensionality 1 x self.size x self.size, between 0 and 1
-function Catch:getStateSpec()
-  return {'int', {1, self.size, self.size}, {0, 1}}
+function Catch:getStateSpace()
+  local state = {}
+  state['name'] = 'Box'
+  state['shape'] = {1, self.size, self.size}
+  state['low'] = {
+    0
+  }
+  state['high'] = {
+    1
+  }
+  return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, between 0 and 2
-function Catch:getActionSpec()
-  return {'int', 1, {0, 2}}
+function Catch:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = 3
+  return action
 end
 
 -- RGB screen of size self.size x self.size
@@ -43,7 +56,7 @@ function Catch:getDisplaySpec()
 end
 
 -- Min and max reward
-function Catch:getRewardSpec()
+function Catch:getRewardSpace()
   return 0, 1
 end
 
@@ -64,7 +77,7 @@ function Catch:redraw()
 end
 
 -- Starts new game
-function Catch:start()
+function Catch:_start()
   -- Reset player and ball
   self.player.x = math.ceil(self.size / 2)
   self.ball.x = torch.random(self.size)
@@ -80,7 +93,7 @@ function Catch:start()
 end
 
 -- Steps in a game
-function Catch:step(action)
+function Catch:_step(action)
   -- Reward is 0 by default
   local reward = 0
 
diff --git a/rlenvs/CliffWalking.lua b/rlenvs/CliffWalking.lua
index 41d029f..4200e4f 100644
--- a/rlenvs/CliffWalking.lua
+++ b/rlenvs/CliffWalking.lua
@@ -5,35 +5,48 @@ local CliffWalking, super = classic.class('CliffWalking', Env)
 -- Constructor
 function CliffWalking:_init(opts)
   opts = opts or {}
+  super._init(self, opts)
 end
 
 -- 2 states returned, of type 'int', of dimensionality 1, where x is 1-12 and y is 1-4
-function CliffWalking:getStateSpec()
-  return {
-    {'int', 1, {1, 12}}, -- x
-    {'int', 1, {1, 4}} -- y
+function CliffWalking:getStateSpace()
+  local state = {}
+  state['name'] = 'Box'
+  state['shape'] = {2}
+  state['low'] = {
+    1, -- x
+    1 -- y
   }
+  state['high'] = {
+    12, -- x
+    4 -- y
+  }
+  return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, between 1 and 4 (up|right|down|left)
-function CliffWalking:getActionSpec()
-  return {'int', 1, {1, 4}}
+function CliffWalking:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = 4
+  return action
 end
 
 -- Min and max reward
-function CliffWalking:getRewardSpec()
+function CliffWalking:getRewardSpace()
   return -100, -1
 end
 
 -- Reset position
-function CliffWalking:start()
+function CliffWalking:_start()
   self.position = {1, 1}
 
   return self.position
 end
 
 -- Move up, right, down or left
-function CliffWalking:step(action)
+function CliffWalking:_step(action)
+  action = action + 1 -- scale action
   local reward = -1
   local terminal = false
 
diff --git a/rlenvs/DynaMaze.lua b/rlenvs/DynaMaze.lua
index 42faaf0..c1b9ddb 100644
--- a/rlenvs/DynaMaze.lua
+++ b/rlenvs/DynaMaze.lua
@@ -5,6 +5,7 @@ local DynaMaze, super = classic.class('DynaMaze', Env)
 -- Constructor
 function DynaMaze:_init(opts)
   opts = opts or {}
+  super._init(self, opts)
 
   -- Set change: none|blocking|shortcut
   self.change = opts.change or 'none'
@@ -27,25 +28,36 @@ function DynaMaze:_init(opts)
 end
 
 -- 2 states returned, of type 'int', of dimensionality 1, where x is 1-9 and y is 1-6
-function DynaMaze:getStateSpec()
-  return {
-    {'int', 1, {1, 9}}, -- x
-    {'int', 1, {1, 6}} -- y
+function DynaMaze:getStateSpace()
+  local state = {}
+  state['name'] = 'Box'
+  state['shape'] = {2}
+  state['low'] = {
+    1, -- x
+    1 -- y
   }
+  state['high'] = {
+    9, -- x
+    6 -- y
+  }
+  return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, between 1 and 4
-function DynaMaze:getActionSpec()
-  return {'int', 1, {1, 4}}
+function DynaMaze:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = 4
+  return action
 end
 
 -- Min and max reward
-function DynaMaze:getRewardSpec()
+function DynaMaze:getRewardSpace()
   return 0, 1
 end
 
 -- Reset position
-function DynaMaze:start()
+function DynaMaze:_start()
   if self.change == 'none' then
     self.position = {1, 4}
   else
@@ -56,7 +68,8 @@ function DynaMaze:start()
 end
 
 -- Move up, right, down or left
-function DynaMaze:step(action)
+function DynaMaze:_step(action)
+  action = action + 1 -- scale action
   local reward = 0
   local terminal = false
 
diff --git a/rlenvs/Env.lua b/rlenvs/Env.lua
index 262c5f4..43817d8 100644
--- a/rlenvs/Env.lua
+++ b/rlenvs/Env.lua
@@ -3,10 +3,51 @@ local classic = require 'classic'
 local Env = classic.class('Env')
 
 -- Denote interfaces
-Env:mustHave('start')
-Env:mustHave('step')
-Env:mustHave('getStateSpec')
-Env:mustHave('getActionSpec')
-Env:mustHave('getRewardSpec')
+Env:mustHave('_start')
+Env:mustHave('_step')
+Env:mustHave('getStateSpace')
+Env:mustHave('getActionSpace')
+Env:mustHave('getRewardSpace')
+
+function Env:_init(opts)
+    if opts.timeStepLimit and opts.maxSteps then
+        self.maxSteps = math.min(opts.timeStepLimit, opts.maxSteps)
+    elseif opts.maxSteps then
+        self.maxSteps = opts.maxSteps
+    elseif opts.timeStepLimit then
+        self.maxSteps = opts.timeStepLimit
+    else
+        self.maxSteps = 1000
+    end
+    if opts.render then
+        require 'image' self.qt = pcall(require, 'qt')
+        if not self.qt then print('Was not able to load qt to render, are you using qlua to run the script?') end
+    end
+    self.zoom = opts.zoom or 1
+    self.currentStep = 1
+end
+
+function Env:step(action)
+    local reward, state, terminal = self:_step(action)
+    if self.currentStep == self.maxSteps then
+        terminal = true
+        self.currentStep = 0
+    end
+    self.currentStep = self.currentStep + 1
+    return reward, state, terminal
+end
+
+function Env:start()
+    self.currentStep = 1
+    local obs = self:_start()
+    return obs
+end
+
+function Env:render()
+    if self.qt and self.getDisplay then
+        self.window = self.window == nil and image.display({ image = self:getDisplay(), zoom = self.zoom }) or self.window
+        image.display({ image = self:getDisplay(), zoom = self.zoom, win = self.window })
+    end
+end
 
 return Env
diff --git a/rlenvs/GridWorld.lua b/rlenvs/GridWorld.lua
index 66fba69..ae4ba34 100644
--- a/rlenvs/GridWorld.lua
+++ b/rlenvs/GridWorld.lua
@@ -6,6 +6,7 @@ local GridWorld, super = classic.class('GridWorld', Env)
 -- Constructor
 function GridWorld:_init(opts)
   opts = opts or {}
+  super._init(self, opts)
 
   -- Cost of moving in world (discretized)
   self.world = torch.Tensor(101, 101):fill(-0.5)
@@ -19,32 +20,44 @@ function GridWorld:_init(opts)
 end
 
 -- 2 states returned, of type 'real', of dimensionality 1, from 0-1
-function GridWorld:getStateSpec()
-  return {
-    {'real', 1, {0, 1}}, -- x
-    {'real', 1, {0, 1}} -- y
+function GridWorld:getStateSpace()
+  local state = {}
+  state['name'] = 'Box'
+  state['shape'] = {2}
+  state['low'] = {
+    0, -- x
+    0 -- y
   }
+  state['high'] = {
+    1, -- x
+    1 -- y
+  }
+  return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, between 1 and 4
-function GridWorld:getActionSpec()
-  return {'int', 1, {1, 4}}
+function GridWorld:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = 4
+  return action
 end
 
 -- Min and max reward
-function GridWorld:getRewardSpec()
+function GridWorld:getRewardSpace()
   return torch.min(self.world), 0
 end
 
 -- Reset position
-function GridWorld:start()
+function GridWorld:_start()
   self.position = {0.2, 0.4}
 
   return self.position
 end
 
 -- Move up, right, down or left
-function GridWorld:step(action)
+function GridWorld:_step(action)
+  action = action + 1 -- scale action
   local terminal = false
 
   -- Move
diff --git a/rlenvs/JacksCarRental.lua b/rlenvs/JacksCarRental.lua
index fa9d3a3..55593ef 100644
--- a/rlenvs/JacksCarRental.lua
+++ b/rlenvs/JacksCarRental.lua
@@ -19,28 +19,40 @@ end
 -- Constructor
 function JacksCarRental:_init(opts)
   opts = opts or {}
+  super._init(self, opts)
 end
 
 -- 2 states returned, of type 'int', of dimensionality 1, for 0-20 cars
-function JacksCarRental:getStateSpec()
-  return {
-    {'int', 1, {0, 20}}, -- Lot 1
-    {'int', 1, {0, 20}} -- Lot 2
+function JacksCarRental:getStateSpace()
+  local state = {}
+  state['name'] = 'Box'
+  state['shape'] = {2}
+  state['low'] = {
+    0, -- Lot 1
+    0 -- Lot 2
   }
+  state['high'] = {
+    20, -- Lot 1
+    20 -- Lot 2
+  }
+  return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, between -5 and 5 (max 5 cars can be moved overnight)
-function JacksCarRental:getActionSpec()
-  return {'int', 1, {-5, 5}} -- Negative numbers indicate transferring cars from lot 2 to lot 1
+function JacksCarRental:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = 10
+  return action
 end
 
 -- Min and max reward
-function JacksCarRental:getRewardSpec()
+function JacksCarRental:getRewardSpace()
   return 0, 200
 end
 
 -- Resets the cars to 10 at each lot
-function JacksCarRental:start()
+function JacksCarRental:_start()
   self.lot1 = 10
   self.lot2 = 10
 
@@ -48,7 +60,8 @@ function JacksCarRental:start()
 end
 
 -- Acts out a day and night for Jack's Car Rental
-function JacksCarRental:step(action)
+function JacksCarRental:_step(action)
+  action = action - 5 -- scale action
   local reward = 0 -- Reward in $
 
   -- Customers rent cars from lot 1 during the day
@@ -78,7 +91,7 @@ function JacksCarRental:step(action)
     self.lot1 = self.lot1 - carsMoved
     self.lot2 = self.lot2 + carsMoved
     reward = reward - 2*carsMoved
-  elseif action < 0 then
+  elseif action < 0 then -- Negative numbers indicate transferring cars from lot 2 to lot 1
     carsMoved = math.min(-action, self.lot2)
     carsMoved = math.min(carsMoved, 20 - self.lot1)
     -- Move cars
diff --git a/rlenvs/Minecraft.lua b/rlenvs/Minecraft.lua
index 8997462..b91dc66 100644
--- a/rlenvs/Minecraft.lua
+++ b/rlenvs/Minecraft.lua
@@ -16,6 +16,8 @@ end
 
 -- Constructor
 function Minecraft:_init(opts)
+  opts = opts or {}
+  super._init(self, opts)
   -- Check libaMalmoLua is available locally
   if not hasLibMalmoLua then
     print("Requires libMalmoLua.so in LUA_CPATH")
@@ -120,16 +122,28 @@ function Minecraft:_init(opts)
 end
 
 -- 2 states returned, of type 'real', of dimensionality 1, from 0-1
-function Minecraft:getStateSpec()
-  return {'real', {3, self.height, self.width}, {0, 1}}
+function Minecraft:getStateSpace()
+  local state = {}
+  state['name'] = 'Box'
+  state['shape'] = {3, self.height, self.width}
+  state['low'] = {
+    0
+  }
+  state['high'] = {
+    1
+  }
+  return state
 end
 
-function Minecraft:getActionSpec()
-  return {'int', 1, {1, #self.actions}}
+function Minecraft:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = #self.actions
+  return action
 end
 
--- Min and max reward
-function Minecraft:getRewardSpec()
+-- Min and max reward (unknown)
+function Minecraft:getRewardSpace()
   return nil, nil
 end
 
@@ -158,7 +172,7 @@ function Minecraft:getRewards(world_rewards)
 end
 
 -- Reset position
-function Minecraft:start()
+function Minecraft:_start()
   local mission = MissionSpec(self.mission_xml, true)
   local mission_record = MissionRecordSpec()
 
@@ -216,7 +230,7 @@ function Minecraft:start()
 end
 
 -- Move up, right, down or left
-function Minecraft:step(action)
+function Minecraft:_step(action)
   -- Do something
   local action = self.actions[action]
   self.agent_host:sendCommand(action)
diff --git a/rlenvs/MountainCar.lua b/rlenvs/MountainCar.lua
index 8d62109..fe1715c 100644
--- a/rlenvs/MountainCar.lua
+++ b/rlenvs/MountainCar.lua
@@ -1,32 +1,47 @@
 local classic = require 'classic'
 
 local MountainCar, super = classic.class('MountainCar', Env)
+MountainCar.timeStepLimit = 200
 
 -- Constructor
 function MountainCar:_init(opts)
   opts = opts or {}
+  opts.timeStepLimit = MountainCar.timeStepLimit
+
+  super._init(self, opts)
 end
 
 -- 2 states returned, of type 'real', of dimensionality 1, with differing ranges
-function MountainCar:getStateSpec()
-  return {
-    {'real', 1, {-0.07, 0.07}}, -- Velocity
-    {'real', 1, {-1.2, 0.6}} -- Position
+function MountainCar:getStateSpace()
+  local state = {}
+  state['name'] = 'Box'
+  state['shape'] = {2}
+  state['low'] = {
+    -0.07, -- Velocity
+    -1.2 -- Position
+  }
+  state['high'] = {
+    0.07, -- Velocity
+    0.6 -- Position
   }
+  return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, between -1 and 1 (left, neutral, right)
-function MountainCar:getActionSpec()
-  return {'int', 1, {-1, 1}}
+function MountainCar:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = 3
+  return action
 end
 
 -- Min and max reward
-function MountainCar:getRewardSpec()
+function MountainCar:getRewardSpace()
   return -2, 0 -- As height = sin(3x) is between -1 and 1, and reward = height - 1
 end
 
 -- Resets the car
-function MountainCar:start()
+function MountainCar:_start()
   -- Reset position and velocity
   self.position = -0.5
   self.velocity = 0
@@ -35,7 +50,8 @@ function MountainCar:start()
 end
 
 -- Drives the car
-function MountainCar:step(action)
+function MountainCar:_step(action)
+  action = action - 1  -- scale action
   -- Calculate height
   local height = math.sin(3*self.position)
 
diff --git a/rlenvs/MultiArmedBandit.lua b/rlenvs/MultiArmedBandit.lua
index 9261221..d4e6c75 100644
--- a/rlenvs/MultiArmedBandit.lua
+++ b/rlenvs/MultiArmedBandit.lua
@@ -5,6 +5,7 @@ local MultiArmedBandit, super = classic.class('MultiArmedBandit', Env)
 -- Constructor
 function MultiArmedBandit:_init(opts)
   opts = opts or {}
+  super._init(self, opts)
 
   -- Restless bandits (with a Gaussian random walk)
   self.restless = opts.restless or false
@@ -19,27 +20,31 @@ function MultiArmedBandit:_init(opts)
 end
 
 -- No state (not a contextual bandit)
-function MultiArmedBandit:getStateSpec()
+function MultiArmedBandit:getStateSpace()
   return nil
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, of the number of arms
-function MultiArmedBandit:getActionSpec()
-  return {'int', 1, {1, self.nArms}}
+function MultiArmedBandit:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = self.nArms
+  return action
 end
 
 -- Min and max rewards unknown when sampling from distributions
-function MultiArmedBandit:getRewardSpec()
+function MultiArmedBandit:getRewardSpace()
   return nil, nil
 end
 
 -- Does nothing (distributions do not reset)
-function MultiArmedBandit:start()
+function MultiArmedBandit:_start()
   return nil
 end
 
 -- Pulls an arm
-function MultiArmedBandit:step(action)
+function MultiArmedBandit:_step(action)
+  action = action + 1 -- scale action
   -- Sample for reward
   local reward = torch.normal(self.armMeans[action], 1)
 
diff --git a/rlenvs/RandomWalk.lua b/rlenvs/RandomWalk.lua
index 8594330..a1df9b2 100644
--- a/rlenvs/RandomWalk.lua
+++ b/rlenvs/RandomWalk.lua
@@ -5,32 +5,39 @@ local RandomWalk, super = classic.class('RandomWalk', Env)
 -- Constructor
 function RandomWalk:_init(opts)
   opts = opts or {}
+  super._init(self, opts)
 end
 
 -- 1 states returned, of type 'int', of dimensionality 1, between 0 and 6 (the terminal states)
-function RandomWalk:getStateSpec()
-  return {'int', 1, {0, 6}} -- Position
+function RandomWalk:getStateSpace()
+  local state = {}
+  state['name'] = 'Discrete'
+  state['n'] = 6
+  return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, between 0 and 1 (left or right)
-function RandomWalk:getActionSpec()
-  return {'int', 1, {0, 1}}
+function RandomWalk:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = 2
+  return action
 end
 
 -- Min and max reward
-function RandomWalk:getRewardSpec()
+function RandomWalk:getRewardSpace()
   return 0, 1
 end
 
 -- Reset position
-function RandomWalk:start()
+function RandomWalk:_start()
   self.position = 3
 
   return self.position
 end
 
 -- Move left or right
-function RandomWalk:step(action)
+function RandomWalk:_step(action)
   local reward = 0
   local terminal = false
 
diff --git a/rlenvs/Taxi.lua b/rlenvs/Taxi.lua
index 61d0ba5..962b90c 100644
--- a/rlenvs/Taxi.lua
+++ b/rlenvs/Taxi.lua
@@ -12,10 +12,14 @@ local classic = require 'classic'
 --]]
 
 local Taxi, super = classic.class('Taxi', Env)
+Taxi.timeStepLimit = 200
 
 -- Constructor
 function Taxi:_init(opts)
   opts = opts or {}
+  opts.timeStepLimit = Taxi.timeStepLimit
+
+  super._init(self, opts)
 
   -- Passenger positions (Red, Green, Blue, Yellow)
   self.rgbyPos = {{0, 4}, {4, 4}, {3, 0}, {0, 0}}
@@ -24,28 +28,42 @@ function Taxi:_init(opts)
 end
 
 -- 4 states returned, of type 'int', of dimensionality 1, where x and y are 0-5, fuel is -1-12, passenger position is 1-5 and destination is 1-4
-function Taxi:getStateSpec()
-  return {
-    {'int', 1, {0, 4}}, -- x
-    {'int', 1, {0, 4}}, -- y
-    {'int', 1, {-1, 12}}, -- Fuel
-    {'int', 1, {1, 5}}, -- Passenger location
-    {'int', 1, {1, 4}}, -- Destination TODO: Work out why there are apparently 5 destination states in the original paper
+function Taxi:getStateSpace()
+  local state = {}
+  state['name'] = 'Box'
+  state['shape'] = {5}
+  state['low'] = {
+    0, -- x
+    0, -- y
+    -1, -- Fuel
+    1, -- Passenger location
+    1 -- Destination TODO: Work out why there are apparently 5 destination states in the original paper
+  }
+  state['high'] = {
+    4, -- x
+    4, -- y
+    12, -- Fuel
+    5, -- Passenger location
+    4 -- Destination
   }
+  return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, where 1-4 is move N, E, S, W, 5 is Pickup, 6 is Putdown and 7 is Fillup
-function Taxi:getActionSpec()
-  return {'int', 1, {1, 7}}
+function Taxi:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
+  action['n'] = 7
+  return action
 end
 
 -- Min and max reward
-function Taxi:getRewardSpec()
+function Taxi:getRewardSpace()
   return -20, 20
 end
 
 -- Reset position, fuel and passenger
-function Taxi:start()
+function Taxi:_start()
   -- Randomise position and fuel
   self.position = {torch.random(0, 4), torch.random(0, 4)}
   self.fuel = torch.random(5, 12)
@@ -90,7 +108,7 @@ function Taxi:validMove(action)
 end
 
 -- Move up, right, down or left
-function Taxi:step(action)
+function Taxi:_step(action)
   local reward = -1
   local terminal = false
 
diff --git a/rlenvs/WindyWorld.lua b/rlenvs/WindyWorld.lua
index 9cba841..00fdce1 100644
--- a/rlenvs/WindyWorld.lua
+++ b/rlenvs/WindyWorld.lua
@@ -5,42 +5,56 @@ local WindyWorld, super = classic.class('WindyWorld', Env)
 -- Constructor
 function WindyWorld:_init(opts)
   opts = opts or {}
+  super._init(self, opts)
 
   -- Allow king's moves (8 directions)
   self.king = opts.king or false
 end
 
 -- 2 states returned, of type 'int', of dimensionality 1, where x is 1-10 and y is 1-7
-function WindyWorld:getStateSpec()
-  return {
-    {'int', 1, {1, 10}}, -- x
-    {'int', 1, {1, 7}} -- y
+function WindyWorld:getStateSpace()
+  local state = {}
+  state['name'] = 'Box'
+  state['shape'] = {5}
+  state['low'] = {
+    1, -- x
+    1 -- y
   }
+  state['high'] = {
+    10, -- x
+    7 -- y
+  }
+  return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, between 1 and 4 (for standard) or 1 and 8 (for king)
-function WindyWorld:getActionSpec()
+function WindyWorld:getActionSpace()
+  local action = {}
+  action['name'] = 'Discrete'
   if self.king then
-    return {'int', 1, {1, 8}}
+    action['n'] = 8
+    return action
   else
-    return {'int', 1, {1, 4}}
+    action['n'] = 4
+    return action
   end
 end
 
 -- Min and max reward
-function WindyWorld:getRewardSpec()
+function WindyWorld:getRewardSpace()
   return -1, -1
 end
 
 -- Reset position
-function WindyWorld:start()
+function WindyWorld:_start()
   self.position = {1, 4}
 
   return self.position
 end
 
 -- Move up, right, down or left
-function WindyWorld:step(action)
+function WindyWorld:_step(action)
+  action = action + 1 -- scale action
   local terminal = false
 
   -- Move
diff --git a/rlenvs/XOWorld.lua b/rlenvs/XOWorld.lua
index 691d61c..72f0ed9 100644
--- a/rlenvs/XOWorld.lua
+++ b/rlenvs/XOWorld.lua
@@ -6,6 +6,7 @@ local XOWorld, super = classic.class('XOWorld', Env)
 -- Constructor
 function XOWorld:_init(opts)
   opts = opts or {}
+  super._init(self, opts)
 
   -- Game mode (all circles, negative, or circles and crosses, negative and positive)
   self.double = opts.double or false
@@ -102,24 +103,36 @@ function XOWorld:_init(opts)
                        {67, 7}, {67, 27}, {67, 47}, {67, 67}}
 end
 
--- 1 state returned, of type 'int', of dimensionality 1 x self.size x self.size, between 0 and 1
-function XOWorld:getStateSpec()
-  return {'int', {1, self.size, self.size}, {0, 1}}
+-- 1 state returned, of type 'real', of dimensionality 3 x 210 x 160, between 0 and 1
+function XOWorld:getStateSpace()
+    local state = {}
+    state['name'] = 'Box'
+    state['shape'] = {1, self.size, self.size}
+    state['low'] = {
+        0
+    }
+    state['high'] = {
+        1
+    }
+    return state
 end
 
 -- 1 action required, of type 'int', of dimensionality 1, between 0 and 3
-function XOWorld:getActionSpec()
-  return {'int', 1, {0, 3}}
+function XOWorld:getActionSpace()
+    local action = {}
+    action['name'] = 'Discrete'
+    action['n'] = 4
+    return action
 end
 
 -- RGB screen of size self.size x self.size
 function XOWorld:getDisplaySpec()
-  return {'real', {3, self.size, self.size}, {0, 1}}
+    return {'real', {3, self.size, self.size}, {0, 1}}
 end
 
 -- Min and max reward
-function XOWorld:getRewardSpec()
-  return -10, 10
+function XOWorld:getRewardSpace()
+    return -10, 10
 end
 
 -- Redraws screen based on state and performs collision detection
@@ -188,7 +201,7 @@ function XOWorld:update()
 end
 
 -- Starts new game
-function XOWorld:start()
+function XOWorld:_start()
   -- Reset time
   self.time = 1
 
@@ -257,7 +270,7 @@ function XOWorld:start()
 end
 
 -- Steps in a game
-function XOWorld:step(action)
+function XOWorld:_step(action)
   -- Move player
   if action == 0 then
     self.x = math.max(self.x - 1, 1)
diff --git a/rlenvs/init.lua b/rlenvs/init.lua
index c29cfc9..8a7f886 100644
--- a/rlenvs/init.lua
+++ b/rlenvs/init.lua
@@ -1,7 +1,7 @@
 local rlenvs = {}
 
 -- Include environments
-rlenvs.Env = require 'rlenvs/Env'
+Env = require 'rlenvs/Env'
 rlenvs.Acrobot = require 'rlenvs/Acrobot'
 rlenvs.Atari = require 'rlenvs/Atari'
 rlenvs.Blackjack = require 'rlenvs/Blackjack'
@@ -25,4 +25,10 @@ for k, v in pairs(rlenvs) do
   end
 end
 
+local envs ={}
+for k,_ in pairs(rlenvs) do
+  envs[#envs+1]=k
+end
+rlenvs.envs = envs
+
 return rlenvs
diff --git a/tests/test.lua b/tests/test.lua
new file mode 100644
index 0000000..3a31ce9
--- /dev/null
+++ b/tests/test.lua
@@ -0,0 +1,41 @@
+require 'torch'
+local rlenvs = require 'rlenvs'
+
+local test = torch.TestSuite()
+local tester
+
+function test.envs()
+    for index, env in ipairs(rlenvs.envs) do
+        local function runTest()
+            local Env = require('rlenvs.' .. env)
+            -- Initialise and start environment
+            local env = Env()
+            local actionSpace = env:getActionSpace()
+            local observation = env:start()
+            -- Pick random action and execute it
+            local action = torch.random(0, actionSpace['n'] - 1)
+            local reward, observation, terminal = env:step(action)
+            -- Display if implemented
+            env:render()
+        end
+
+        if env == 'Atari' then
+            local hasALEWrap = pcall(require, 'alewrap')
+            if not hasALEWrap then
+                tester:assert(pcall(runTest), 'Failed to run rlenv environment ' .. env)
+            end
+        elseif env == 'Minecraft' then
+            local hasSocket = pcall(require, 'socket')
+            local hasLibMalmoLua = pcall(require, 'libMalmoLua')
+            if not hasSocket and hasLibMalmoLua then
+                tester:assert(pcall(runTest), 'Failed to run rlenv environment ' .. env)
+            end
+        else
+            tester:assert(pcall(runTest), 'Failed to run rlenv environment ' .. env)
+        end
+    end
+end
+
+tester = torch.Tester()
+tester:add(test)
+tester:run()
\ No newline at end of file