Just wanted to leave a little feedback here since this game doesn't seem to be very well known in the GB homebrew scene. This is a very impressive survivors-like. The character and enemy animation is very charming, and the upgrade path is addictive. Enjoyed the music, too.
I just beat it on Impossible difficulty after buying everything, and I'm so impressed that the game doesn't completely break when the speed and enemy count gets cranked up to the max. Sure there's some slowdown when it's at its craziest, but to have this running on GB specs is quite a feat.
My only negative feedback is related to the marketing. Is the game called Legion of Devil or Legion of Evil? This page lists it as both, which is not helpful for name recognition, and initially led me to expect an unprofessional game (which this definitely is not). I'd go with Legion of Evil, for what it's worth.
That said, I'm having trouble getting into the final room of world 3-3. There is no path to the door on the right, and the path from the bottom is inaccessible even though it appears to be an open, normal path. It doesn't allow you to go up to enter the room. Am I missing something?