I agree about the controls. I lean back in my chair and one hand on arrow keys, add gamepad support. bing bang boom done, right? right? RIGHT? haha I'll probably go back at some point and make the changes you've suggested, letting left handed/WASD controls feel better and more natural for players who perfer that. (most, apparently?).
I agree with all of your feedback. Menu, of course - I also need to implement a high-contrast/color blind mode, and a way to enable that. I'm glad you mentioned the level design and challenge progression. Being frustrated with the progression and curve, and roughly but not specifically knowing the steps to improve it was one of my biggest blocks. Probably the one major component that kept me, for months, from wanting to 'put this in the wild'. How much should the puzzle be platforming? Timing? Shouldn't it all be the tricky mind-bending parts? I went back and forth with these questions a lot. And still do!
I really appreciate the time you spent to play through this and the constructive criticism. I'm really blown away by how friendly and supportive the itch.io community has been, even for this one little project! I'm seriously inspired and more confident on bringing more of my projects to light here (you know... when they're done). Thanks!