Might only be usable on Windows, I dunno.
This is supposed to teach a very important lesson about using the right form of there/their/they’re. You are a little robot, and you HATE it when someone uses the wrong form of there/their/they’re. You are presented with a statement, and must discern which from of there/their/they’re is the right one, and shoot the impostors. If you shoot the right form of there/their/they’re, you will die. If an impostor touches you, you will die. Each time you kill an impostor, you get 10 points, as tallied in the upper left-hand corner of the screen. Each time you kill an impostor, it spawns 2 more impostors, representing our endless futile struggle against bad grammar.