diff --git a/arena.c b/arena.c
index 9616cc5..90a45bd 100644
--- a/arena.c
+++ b/arena.c
@@ -25,19 +25,28 @@ void setupWallSprites() {
   buildCompiledSprite(
     &sprite_arenaWallTop,
     &arenaWallTop,
-    20, 20
+    SPRITE_ARENAWALLTOP_WIDTH,
+    SPRITE_ARENAWALLTOP_HEIGHT,
+    SPRITE_ARENAWALLTOP_OFFSET_X,
+    SPRITE_ARENAWALLTOP_OFFSET_Y
   );
 
   buildCompiledSprite(
     &sprite_arenaWallSide,
     &arenaWallSide,
-    20, 20
+    SPRITE_ARENAWALLSIDE_WIDTH,
+    SPRITE_ARENAWALLSIDE_HEIGHT,
+    SPRITE_ARENAWALLSIDE_OFFSET_X,
+    SPRITE_ARENAWALLSIDE_OFFSET_Y
   );
 
   buildCompiledSprite(
     &sprite_arenaFloor,
     &arenaFloor,
-    20, 20
+    SPRITE_ARENAFLOOR_WIDTH,
+    SPRITE_ARENAFLOOR_HEIGHT,
+    SPRITE_ARENAFLOOR_OFFSET_X,
+    SPRITE_ARENAFLOOR_OFFSET_Y
   );
 }
 
diff --git a/bin/build_spritesheet_asm.rb b/bin/build_spritesheet_asm.rb
index b80f06b..3d6fdab 100755
--- a/bin/build_spritesheet_asm.rb
+++ b/bin/build_spritesheet_asm.rb
@@ -68,9 +68,10 @@ C_TEMPLATE = <<~C
 
   <% sprites.each do |sprite| %>
   extern void <%= sprite.function_name %>(byte *);
+  <% sprite.constants.each do |constant, value| %>
+  #define <%= constant %> (<%= value %>)
+  <% end %>
   <% end %>
-
-  // TODO: something with bounds checking here
 
   #endif
 C
@@ -102,6 +103,17 @@ class AssemblerSprite
     "#{@prefix}_#{@name}"
   end
 
+  def constants
+    [
+      ['WIDTH', @pixel_data[0].length],
+      ['HEIGHT', @pixel_data.length],
+      ['OFFSET_X', @offset_x],
+      ['OFFSET_Y', @offset_y]
+    ].map do |suffix, value|
+      ["#{function_name.upcase}_#{suffix}", value]
+    end
+  end
+
   def bytes
     return @bytes if defined?(@bytes)
 
diff --git a/game.c b/game.c
index cbd3f83..09bd0c0 100644
--- a/game.c
+++ b/game.c
@@ -18,7 +18,7 @@
 struct BMPImage spritesheetImage;
 struct VGAColor vgaColors[256];
 
-struct SpriteRender rabbit, mouse, bullet, enemy;
+struct CompiledSpriteRender rabbit, mouse, bullet, enemy;
 struct RabbitPosition rabbitPosition = {
   .rabbitPosition = { 60, 60 },
   .rabbitLimits = { { 20, 20 }, { 180, 180 } },
@@ -162,40 +162,43 @@ void maybeSpawnEnemy() {
 }
 
 void setupEnemySprites() {
-  buildSpriteFromSpritesheet(
-    &spritesheetImage,
+  buildCompiledSprite(
+    &sprite_enemy,
     &enemy,
-    0, 20, 16, 16
+    SPRITE_ENEMY_WIDTH,
+    SPRITE_ENEMY_HEIGHT,
+    SPRITE_ENEMY_OFFSET_X,
+    SPRITE_ENEMY_OFFSET_Y
   );
 }
 
 void setupRabbitSprites() {
-  buildSpriteFromSpritesheet(
-    &spritesheetImage,
+  buildCompiledSprite(
+    &sprite_rabbit,
     &rabbit,
-    0, 20, 16, 16
+    SPRITE_RABBIT_WIDTH,
+    SPRITE_RABBIT_HEIGHT,
+    SPRITE_RABBIT_OFFSET_X,
+    SPRITE_RABBIT_OFFSET_Y
   );
 
-  rabbit.offsetX = 8;
-  rabbit.offsetY = 15;
-
-  buildSpriteFromSpritesheet(
-    &spritesheetImage,
+  buildCompiledSprite(
+    &sprite_mouse,
     &mouse,
-    16, 20, 8, 8
+    SPRITE_MOUSE_WIDTH,
+    SPRITE_MOUSE_HEIGHT,
+    SPRITE_MOUSE_OFFSET_X,
+    SPRITE_MOUSE_OFFSET_Y
   );
 
-  mouse.offsetX = 4;
-  mouse.offsetY = 4;
-
-  buildSpriteFromSpritesheet(
-    &spritesheetImage,
+  buildCompiledSprite(
+    &sprite_bullet,
     &bullet,
-    16, 28, 4, 4
+    SPRITE_BULLET_WIDTH,
+    SPRITE_BULLET_HEIGHT,
+    SPRITE_BULLET_OFFSET_X,
+    SPRITE_BULLET_OFFSET_Y
   );
-
-  bullet.offsetX = 1;
-  bullet.offsetY = 1;
 }
 
 struct MouseStatus mouseStatus;
@@ -204,7 +207,7 @@ void renderMouse() {
   mouse.x = rabbitPosition.mousePosition[0];
   mouse.y = rabbitPosition.mousePosition[1];
 
-  drawSprite(&mouse);
+  drawCompiledSprite(&mouse);
   drawPixel(rabbitPosition.mouseDotPosition[0], rabbitPosition.mouseDotPosition[1], 2);
 }
 
@@ -212,7 +215,7 @@ void renderRabbit() {
   rabbit.x = rabbitPosition.rabbitPosition[0];
   rabbit.y = rabbitPosition.rabbitPosition[1];
 
-  drawSprite(&rabbit);
+  drawCompiledSprite(&rabbit);
 }
 
 void renderEnemies() {
@@ -224,7 +227,7 @@ void renderEnemies() {
     enemy.x = enemyPosition[i].enemyPosition[0];
     enemy.y = enemyPosition[i].enemyPosition[1];
 
-    drawSprite(&enemy);
+    drawCompiledSprite(&enemy);
   }
 }
 
@@ -237,7 +240,7 @@ void renderRabbitBullets() {
     bullet.x = rabbitBulletPosition[i].x;
     bullet.y = rabbitBulletPosition[i].y;
 
-    drawSprite(&bullet);
+    drawCompiledSprite(&bullet);
   }
 }
 
diff --git a/makefile b/makefile
index 32aab2c..41c5bac 100644
--- a/makefile
+++ b/makefile
@@ -13,6 +13,9 @@ system/system.lib: .SYMBOLIC
 .asm.o:
 	wasm $<
 
+sprites.asm: sprtsht.bmp spritesheet.yml
+	bin/build_spritesheet_asm.rb
+
 game.exe: $(obj) system/system.lib
   wcl386 -q -bt=dos -l=dos4g $(obj) system/system.lib
 
diff --git a/sprites.asm b/sprites.asm
index 79140ea..6c271c5 100644
--- a/sprites.asm
+++ b/sprites.asm
@@ -1251,12 +1251,12 @@ sprite_rabbit_:
   mov BYTE PTR [eax + -1921], 1
   mov BYTE PTR [eax + -1920], 1
   mov BYTE PTR [eax + -1602], 1
-  mov BYTE PTR [eax + -1601], 1
-  mov BYTE PTR [eax + -1600], 1
+  mov BYTE PTR [eax + -1601], 2
+  mov BYTE PTR [eax + -1600], 2
   mov BYTE PTR [eax + -1599], 1
   mov BYTE PTR [eax + -1282], 1
-  mov BYTE PTR [eax + -1281], 1
-  mov BYTE PTR [eax + -1280], 1
+  mov BYTE PTR [eax + -1281], 2
+  mov BYTE PTR [eax + -1280], 2
   mov BYTE PTR [eax + -1279], 1
   mov BYTE PTR [eax + -961], 1
   mov BYTE PTR [eax + -960], 1
@@ -1351,12 +1351,12 @@ sprite_enemy_:
   mov BYTE PTR [eax + -1921], 1
   mov BYTE PTR [eax + -1920], 1
   mov BYTE PTR [eax + -1602], 1
-  mov BYTE PTR [eax + -1601], 1
-  mov BYTE PTR [eax + -1600], 1
+  mov BYTE PTR [eax + -1601], 2
+  mov BYTE PTR [eax + -1600], 2
   mov BYTE PTR [eax + -1599], 1
   mov BYTE PTR [eax + -1282], 1
-  mov BYTE PTR [eax + -1281], 1
-  mov BYTE PTR [eax + -1280], 1
+  mov BYTE PTR [eax + -1281], 2
+  mov BYTE PTR [eax + -1280], 2
   mov BYTE PTR [eax + -1279], 1
   mov BYTE PTR [eax + -961], 1
   mov BYTE PTR [eax + -960], 1
diff --git a/sprites.h b/sprites.h
index 4beed32..b88bef1 100644
--- a/sprites.h
+++ b/sprites.h
@@ -6,19 +6,80 @@
 
 extern void sprite_arenaWallTop(byte *);
 
+#define SPRITE_ARENAWALLTOP_WIDTH (20)
+
+#define SPRITE_ARENAWALLTOP_HEIGHT (20)
+
+#define SPRITE_ARENAWALLTOP_OFFSET_X (0)
+
+#define SPRITE_ARENAWALLTOP_OFFSET_Y (0)
+
+
 extern void sprite_arenaWallSide(byte *);
 
+#define SPRITE_ARENAWALLSIDE_WIDTH (20)
+
+#define SPRITE_ARENAWALLSIDE_HEIGHT (20)
+
+#define SPRITE_ARENAWALLSIDE_OFFSET_X (0)
+
+#define SPRITE_ARENAWALLSIDE_OFFSET_Y (0)
+
+
 extern void sprite_arenaFloor(byte *);
 
+#define SPRITE_ARENAFLOOR_WIDTH (20)
+
+#define SPRITE_ARENAFLOOR_HEIGHT (20)
+
+#define SPRITE_ARENAFLOOR_OFFSET_X (0)
+
+#define SPRITE_ARENAFLOOR_OFFSET_Y (0)
+
+
 extern void sprite_rabbit(byte *);
 
+#define SPRITE_RABBIT_WIDTH (16)
+
+#define SPRITE_RABBIT_HEIGHT (16)
+
+#define SPRITE_RABBIT_OFFSET_X (8)
+
+#define SPRITE_RABBIT_OFFSET_Y (8)
+
+
 extern void sprite_mouse(byte *);
 
+#define SPRITE_MOUSE_WIDTH (8)
+
+#define SPRITE_MOUSE_HEIGHT (8)
+
+#define SPRITE_MOUSE_OFFSET_X (4)
+
+#define SPRITE_MOUSE_OFFSET_Y (4)
+
+
 extern void sprite_bullet(byte *);
 
+#define SPRITE_BULLET_WIDTH (4)
+
+#define SPRITE_BULLET_HEIGHT (4)
+
+#define SPRITE_BULLET_OFFSET_X (1)
+
+#define SPRITE_BULLET_OFFSET_Y (1)
+
+
 extern void sprite_enemy(byte *);
 
+#define SPRITE_ENEMY_WIDTH (16)
+
+#define SPRITE_ENEMY_HEIGHT (16)
+
+#define SPRITE_ENEMY_OFFSET_X (8)
+
+#define SPRITE_ENEMY_OFFSET_Y (8)
+
 
-// TODO: something with bounds checking here
 
 #endif
diff --git a/spritesheet.xcf b/spritesheet.xcf
index 36ea740..c2b3fb2 100644
Binary files a/spritesheet.xcf and b/spritesheet.xcf differ
diff --git a/sprtsht.bmp b/sprtsht.bmp
index 39233e5..2525951 100644
Binary files a/sprtsht.bmp and b/sprtsht.bmp differ
diff --git a/system/vga.c b/system/vga.c
index 1ff251c..c34e54b 100644
--- a/system/vga.c
+++ b/system/vga.c
@@ -54,11 +54,15 @@ void buildCompiledSprite(
   void (*code)(byte *),
   struct CompiledSpriteRender *compiledSpriteRender,
   int width,
-  int height
+  int height,
+  int offsetX,
+  int offsetY
 ) {
   compiledSpriteRender->code = code;
   compiledSpriteRender->width = width;
   compiledSpriteRender->height = height;
+  compiledSpriteRender->offsetX = offsetX;
+  compiledSpriteRender->offsetY = offsetY;
 }
 
 void drawPixel(int x, int y, int color) {
@@ -101,7 +105,7 @@ void drawCompiledSprite(struct CompiledSpriteRender* compiledSprite) {
   compiledSprite->code(drawBufferPos);
 }
 
-void getSpriteBounds(struct SpriteRender *sprite, struct SpriteBounds *bounds) {
+void getSpriteBounds(struct CompiledSpriteRender *sprite, struct SpriteBounds *bounds) {
   bounds->top = sprite->y - sprite->offsetY;
   bounds->bottom = bounds->top + sprite->height;
 
diff --git a/system/vga.h b/system/vga.h
index 0619c4e..e2bb1ab 100644
--- a/system/vga.h
+++ b/system/vga.h
@@ -34,6 +34,8 @@ struct CompiledSpriteRender {
   int y;
   unsigned int width;
   unsigned int height;
+  int offsetX;
+  int offsetY;
 };
 
 struct SpriteBounds {
@@ -48,8 +50,13 @@ void drawPixel(int x, int y, int color);
 void drawSprite(struct SpriteRender *sprite);
 void drawCompiledSprite(struct CompiledSpriteRender *compiledSprite);
 void buildSpriteFromSpritesheet(struct BMPImage*, struct SpriteRender*, int, int, int, int);
-void buildCompiledSprite(void (*)(byte *), struct CompiledSpriteRender*, int width, int height);
-void getSpriteBounds(struct SpriteRender *sprite, struct SpriteBounds *bounds);
+void buildCompiledSprite(
+  void (*)(byte *),
+  struct CompiledSpriteRender*,
+  int width, int height,
+  int offsetX, int offsetY
+);
+void getSpriteBounds(struct CompiledSpriteRender *sprite, struct SpriteBounds *bounds);
 
 byte *initializeDrawBuffer();
 byte *getDrawBuffer();