Awesome job. You really nailed the metroidvania vibe, complete with power-ups, exploration, and a bit of lore.
The art was simple but effective. Overall it look great and I think it fit the game's theme very nicely.
I particularly liked the player's design and animation.
Music and sfx were also nice so no complaints there.
And the platforming was solid. It was really satisfying moving around the world, and at no point did I get frustrated trying to make a jump, or sliding off of platforms.