Forget.Me.Not is very much like Pacman. You're a little dude going around in a maze eating stuff, but it does have a few differentiating factors. Once you eat everything a lock appears, so hopefully you grabbed that key. The other use of the key is to guard your butt because, you see, your little dude automatically shoots ahead of you as you move and since the mazes wrap around on themsleves (like in Pacman), it's entirely possible to shoot yourself on a long straightaway. The key will block thoes shots. It's much better to shoot the enemies tha randomly spawn in (they explode into food to collect) but be careful because an enemy can separate you from your key.

While this is a clear variation on Pacman and not as good as Pacman (not much is), it's a fun little diversion and it's free.