diff --git a/flake.nix b/flake.nix
index 76db40b..e3cc328 100644
--- a/flake.nix
+++ b/flake.nix
@@ -23,9 +23,8 @@
           nativeBuildInputs = [
             just
             lua-language-server
-            nushell
-            pixelorama
             playdate-sdk-pkg
+            tup
           ];
         };
   };
diff --git a/justfile b/justfile
index 04d0f73..5ca317c 100644
--- a/justfile
+++ b/justfile
@@ -8,6 +8,5 @@ alias s := simu
 simu: build
     PlaydateSimulator {{ bin }}
 
-alias pxl := pixelorama
-pixelorama:
-    pixelorama
+cook-assets:
+    @(which aseprite > /dev/null) || (echo "Missing aseprite program"; exit 1)
diff --git a/src/img/level_01.aseprite b/src/img/level_01.aseprite
new file mode 100644
index 0000000..0e0c3dc
Binary files /dev/null and b/src/img/level_01.aseprite differ
diff --git a/src/main.lua b/src/main.lua
index 2717867..98db2ae 100644
--- a/src/main.lua
+++ b/src/main.lua
@@ -19,10 +19,6 @@ function gameInit()
   atlas = gfx.imagetable.new("img/bg_atlas")
 end
 
--- Now we'll call the function above to configure our game.
--- After this runs (it just runs once), nearly everything will be
--- controlled by the OS calling `playdate.update()` 30 times a second.
-
 gameInit()
 
 function playdate.update()
@@ -31,17 +27,18 @@ function playdate.update()
   -- Note that it is possible for more than one of these directions
   -- to be pressed at once, if the user is pressing diagonally.
 
+  local speed = 5
   if playdate.buttonIsPressed(playdate.kButtonUp) then
     playerSprite:moveBy(0, -2)
   end
   if playdate.buttonIsPressed(playdate.kButtonRight) then
-    playerSprite:moveBy(2, 0)
+    playerSprite:moveBy(speed, 0)
   end
   if playdate.buttonIsPressed(playdate.kButtonDown) then
     playerSprite:moveBy(0, 2)
   end
   if playdate.buttonIsPressed(playdate.kButtonLeft) then
-    playerSprite:moveBy(-2, 0)
+    playerSprite:moveBy(-speed, 0)
   end
 
   -- Call the functions below in playdate.update() to draw sprites and keep