Downloaded the demo and it works just fine, no big bugs found in the 30 minutes I played. Need to gid gud as I got kicked back into the menu at level 11 with around 400 deaths on easy haha. Don't know if it's a bug, hidden timer/counter, or I just pressed a wrong button or something.
Only thing I found is that she wears her normal costume in the idle animation but I just believe that you just didn't got to that till now, and the costumes are more saturated than the default one.
Also when the game is running in background it still receives control inputs. Might be nice if it pauses the game if not in focus.
The design of the levels is nice and the difficulty increases in nice steps without sudden jumps and when new level mechanics are added they don't ovelwhelm because of that. The controls are nice and tight showing me how bad I really am, haha.