Conceptually, this game's not bad, just another not-Roguelike. I myself don't think this game is hard but, and there is no nice way to say it, the controls are horrible.
The character moves way too fast considering just how small most of the rooms are. The jumps feel really bad in general as well, not only is it way too high but the gravity way too instant as well.
I don't know how to really express this.. controls are something you FEEL and it's hard putting something like that in words but the main idea is: reduce speed, reduce the jump strength and, I'm not sure how you handle the gravity but you should look at it and make some changes.
With some reworking on how movement works(maybe even add a duck button) I'm sure this could be a good game.
Good luck with it.