Adventure Time: Billy the Giant Hunter

This free online game has a very interesting way to eliminate enemies: a hero runs around a small monster-like planet and passes through it to reduce the surface and volume. When some smaller monster is at the exit, they kill it. But you can't hit a little monster directly when you face it on the planet surface, it takes some of your life. You won't take too long; when the given time is up, you will lose the level. Also, if you are not precise enough and you meet a small monster on the way out, it can damage you. So make sure you play a good game. Oh by the way, it would be nice to play with the sound on as it helps a bit to understand if you actually get the monsters and if your hero is damaged by their encounter.