Ok, as far as aesthetics and theme go, I'm totally on board, it really catches my attention. Regarding the gameplay, it's similar to Vampire Survivors, which is fine. In fact, the mechanic of making a deal with the Devil, gaining power but also gaining disadvantages, is interesting. I see the 'Build to scale' theme as needing to know which advantages to build up to progress in the game. It's like choosing a build in a MOBA.
My observations are as follows: the flying enemies are as fast as you, so sometimes you take damage for free; the sound when killing large groups of enemies becomes tedious; and when you make a deal with the Devil, I would like it if, even after the deal, it told me what I agreed to.
In summary, great game, beautiful art, solid core, a diamond in the rough.
Funny thing sharing with someone a game with a same idea, the "make a deal with the devil"