I really loved this one! It looks simple, but I found there was a surprising amount of skill and nuance required to find the right areas, and to get just barely close enough to the enemies without getting hit. To slightly add onto what another commenter said, I think it would be cool if there was a different incentive to kill enemies other than just passing the barrier to the next room - for example, maybe your attack area gets larger with every enemy you kill, which would really allow you to ramp up the scale and size of enemies later on and force the player to put some more thought into killing as many enemies as possible to "level up" in time for the bigger baddies :). Anyways. super fun, great job!