Very nice game mechanics and polished level design for the timeframe! You managed to do a lot with the simplicity of the one-button controls. I thought the progression in difficulty and the introduction of new abilities was very thoughtful and well-balanced. I've been trying to learn more about game design lately, and based on some things I've seen about the "metroidvania" genre, I'm wondering if this qualifies as one? I think it does at least partially, since you have the exploration gated by new abilities aspect. I definitely was not prepared for the blood particle effects and metal music, but they were hilarious!