CAT INSTRUCTIONS: Defend the cheese. When the mouse dies, he will drop yarn. You must retrieve this. If you attempt to not retrieve it, you will be slowly dragged in. Click to barf a hairball. The only way to defeat a Mechamouse is with a hairball. To defeat a normal mouse, touch it.
MOUSE INSTRUCTIONS: Get to the cheese. Once you do, you will become a mechamouse. Then, you can click to create a plasma beam to kill cats. The cat always respawns on his PlushCush(tm). You can spawn-kill him. Beware, if you touch him in any form, you die.