I really like the idea of the demon gaining an ability at same time as you do, I think that's a pretty good use of the theme! I like that you can see what abilities the demon gained as well that's good to know and I'm quite impressed with the amount of abilities you have managed to include! The portrait of the demon in the dialogue and the icons of the abilities look very good too! Also, I like the detail of the demon having different things to say when you die.
I'd just say I find the movement very slow, it makes the game feel more difficult than it should be, the controls take a lot of getting used to, but it's okay I take that as part of the challenge lmao