This game seems needlessly hard. For starters, you only have a melee weapon at the start so you get super close to all your enemies. Combine this with you low HP (2 -3 hits if you're lucky) and the fact that enemies respawn once you leave a room, some enemies like the birds can move through walls, and that dying sends you back to the title screen, playing the game just seems too much like a chore.
I would say give the player a gun at the start. The knife is way too weak as a starting weapon. And Increase HP a bit or at least give us checkpoints so it's not a hard reset on death.
I did like the art for the game, and the narrative was intriguing as well. It definitely has a Cave Story vibe to it, and I think if the difficulty was toned down a bit, a lot of people would enjoy playing this game.