Thank you so much for the honest feedback and playing my game!
For the controls I took some inspiration from Celeste. But I've got a lot of feedback that it turned out to be too fast. Something I need to improve on. Maybe taking inspiration from a precision platformer was not the best decision.
As for the map, there was one. I might not have done a great job to communicate that, though. (M on keyboard or the options button on the gamepad)
The sprite size is also something I just changed for the post-jam version. Or to be precise, not the sprite size, but the resolution.
You are definitely right about it being bleak and that the areas looked all the same. I had to improvise towards the end and used some external assets and modified them. As long as you give credits you are allowed to do that. But it would have been cooler to do everything by myself. I agree.
For the boss I also see that I need to improve there. It was the first boss I ever coded, so I am happy with the result, even though I realise there is a lot that could be better about it. :)