Decent base but there's a lot of jank here. For one thing, jumps dont reset when leaving a platform, so you can jump in midair without double jump as long as you didnt jump when you were still on the ground. The controls are also really weird and don't feel like they were designed with a 2d game in mind - mouse to attack in a game with no aiming is particularly strange. Dodging felt pretty inconsistent which might also have to do with the controls - shift is always a bit of an awkward key to reach and press quickly.
The enemies also feel way too responsive and agile compared to the player and often felt more difficult than the bosses who had relatively more thought out attack patterns and longer telegraphs. The shielded enemy in particular was impossible to defeat because it would turn around immediately if you ever got behind it.
The lack of a typical pause menu in a game that's fullscreen by default is also a bit of a problem, I had to use alt+f4 to quit. Aside from that, after beating the demon general the next room warp just didn't lead anywhere. It's understandable if the rest of the game is incomplete but it would be nice to have some indication of that instead of just a broken warp.
All that said I did have fun with this, and it's definitely really appealing visually. Soundtrack was good too, nice work on that.