What do the coins do?
Does the bullet color need to match the 'world' color to kill things?
What weapons are there, or is the 'change weapon' strictly to change bullet color?
These are a couple of the questions that perhaps you should answer in the directions. I don't know what the other game looks like, but this version should be self-contained and have its own directions. Otherwise, the game is conceptually cute, but I'm kinda iffy on the specifics. Thanks.