Well we're not artists nor musicians, so those we obviously have to get them somewhere to start with. It's not everyones cup of tea and we didn't have someone who could do those in our team unfortunately. But I do understand your point, but still I would argue that most of the game was made by us :D From creating the story, to the coding, to the gameplay, to making cutscenes and building everything together and things like boss having same powerUps as your choices/etc, so even with us not making the art ourselves I wouldn't say that we didn't contribute.
Dimension wise I would say that mental health is a dimension of yourself and fighting your inner demons takes you into your own head and facing yourself as the main boss is part of it and that's in a different "dimension". That's how we liked to think the theme. We didn't want to just go with the dimension changing, we wanted to think other aspects of the word dimension as in having two worlds (the real one where the cutscenes take place and the gameplay where you face your inner demons and fights inside your head). Mental dimensions and a lot that revolves around that.
Yeah I completely agree on the contrast of these two art styles, as mentioned before unfortunately we had to go with what we had and we didn't want the art to be the same, since we wanted to show the dimensions of those two separate worlds and how the person sees himself in his head is different.
Balancing the game for sure is difficult and don't get me wrong we worked HARD on that and in the end we felt like we found somewhat a working solution and the feedback I got it seems people have got to the end. It can be beaten with other PowerUps as well, but obviously speed works for one kind of tactic.
Just tried to bring our ideas/thoughts on your points and I do appreciate the honest and indepth feedback and don't take my answers as attacks on your points, they're good questions and I appreciate them and I hoped that I was able to open our thought process and answer your questions :) !