For a first game, this is really good! I loved the artwork, and the movement felt pretty good. I also really liked the mysterious music, it fit the aesthetic really well.
I got lost trying to find the remaining enemies on some of the bigger levels, but eventually managed to beat the game. It may be nice to have some sort of mechanic where stepping on the red square gives you an indicator of where the remaining enemies are. You could also exploit some of the pathfinding by getting enemies stuck on holes, as well as just shooting them from farther away before you’re in their sights.