diff --git a/games/grid-world/game.jl b/games/grid-world/game.jl
index c195359d..11be2cb3 100644
--- a/games/grid-world/game.jl
+++ b/games/grid-world/game.jl
@@ -12,50 +12,47 @@ const RL = CommonRLInterface
 # episode. Because time is not captured in the state, this introduces a slight bias in
 # the value function.
 const EPISODE_LENGTH_BOUND = 200
+const SIZE = SA[10, 10]
+const REWARDS =     Dict(
+		    SA[9,3] =>   1.0,
+		    SA[8,8] =>   0.3,
+		    SA[4,3] =>  -1.0,
+		    SA[4,6] =>  -0.5)
 
 mutable struct World <: AbstractEnv
-  size::SVector{2, Int}
-  rewards::Dict{SVector{2, Int}, Float64}
-  state::SVector{2, Int}
+  position ::SVector{2, Int}
   time :: Int
 end
 
 function World()
-  rewards = Dict(
-    SA[9,3] =>  10.0,
-    SA[8,8] =>   3.0,
-    SA[4,3] => -10.0,
-    SA[4,6] =>  -5.0)
   return World(
-    SA[10, 10],
-    rewards,
     SA[rand(1:10), rand(1:10)],
     0)
 end
 
-RL.reset!(env::World) = (env.state = SA[rand(1:env.size[1]), rand(1:env.size[2])])
+RL.reset!(env::World) = (env.position = SA[rand(1:SIZE[1]), rand(1:SIZE[2])])
 RL.actions(env::World) = [SA[1,0], SA[-1,0], SA[0,1], SA[0,-1]]
-RL.observe(env::World) = env.state
+RL.observe(env::World) = env.position
 
 RL.terminated(env::World) =
-  haskey(env.rewards, env.state) || env.time > EPISODE_LENGTH_BOUND
+  haskey(REWARDS, env.position) || env.time > EPISODE_LENGTH_BOUND
 
 function RL.act!(env::World, a)
   # 40% chance of going in a random direction (=30% chance of going in a wrong direction)
   if rand() < 0.4
       a = rand(actions(env))
   end
-  env.state = clamp.(env.state + a, SA[1,1], env.size)
+  env.position = clamp.(env.position + a, SA[1,1], SIZE)
   env.time += 1
-  return get(env.rewards, env.state, 0.0)
+  return get(REWARDS, env.position, 0.0)
 end
 
 @provide RL.player(env::World) = 1 # An MDP is a one player game
 @provide RL.players(env::World) = [1]
-@provide RL.observations(env::World) = [SA[x, y] for x in 1:env.size[1], y in 1:env.size[2]]
-@provide RL.clone(env::World) = World(env.size, copy(env.rewards), env.state, env.time)
-@provide RL.state(env::World) = env.state
-@provide RL.setstate!(env::World, s) = (env.state = s)
+@provide RL.observations(env::World) = [SA[x, y] for x in 1:SIZE[1], y in 1:SIZE[2]]
+@provide RL.clone(env::World) = World(env.position, env.time)
+@provide RL.state(env::World) = env.position
+@provide RL.setstate!(env::World, s) = (env.position = s)
 @provide RL.valid_action_mask(env::World) = BitVector([1, 1, 1, 1])
 
 # Additional functions needed by AlphaZero.jl that are not present in 
@@ -64,11 +61,11 @@ end
 # CommonRLInterfaceWrapper.
 
 function GI.render(env::World)
-  for y in reverse(1:env.size[2])
-    for x in 1:env.size[1]
+  for y in reverse(1:SIZE[2])
+    for x in 1:SIZE[1]
       s = SA[x, y]
-      r = get(env.rewards, s, 0.0)
-      if env.state == s
+      r = get(REWARDS, s, 0.0)
+      if env.position == s
         c = ("+",)
       elseif r > 0
         c = (crayon"green", "o")
@@ -84,7 +81,7 @@ function GI.render(env::World)
 end
 
 function GI.vectorize_state(env::World, state)
-  v = zeros(Float32, env.size[1], env.size[2])
+  v = zeros(Float32, SIZE[1], SIZE[2])
   v[state[1], state[2]] = 1
   return v
 end
@@ -107,8 +104,8 @@ function GI.read_state(env::World)
     @assert length(s) == 2
     x = parse(Int, s[1])
     y = parse(Int, s[2])
-    @assert 1 <= x <= env.size[1]
-    @assert 1 <= y <= env.size[2]
+    @assert 1 <= x <= SIZE[1]
+    @assert 1 <= y <= SIZE[2]
     return SA[x, y]
   catch e
     return nothing
diff --git a/games/grid-world/params.jl b/games/grid-world/params.jl
index 955f16d3..412ec43a 100644
--- a/games/grid-world/params.jl
+++ b/games/grid-world/params.jl
@@ -37,7 +37,6 @@ learning = LearningParams(
   use_gpu=false,
   use_position_averaging=false,
   samples_weighing_policy=CONSTANT_WEIGHT,
-  rewards_renormalization=10,
   l2_regularization=1e-4,
   optimiser=Adam(lr=5e-3),
   batch_size=64,