with all due respect, I think you might be getting the wrong message. The controls felt wonderful, and the game looked wonderful. The way the levels were built, however, were the thing I dislike the most. for example, in the very first room on one level, you needed to jump past these two pig things that would shoot bullets at you and dodge a laser blast. It was so dang hard getting the timing right and watching all of these threats at once that it made this portion of the game terrible for me. Another issue was the fact that according to the level design, you taught us that we could jump on slimes. However, when I tried to jump on anything else, I died. This is something else that frustrated and confused me. I would recommend learning how other developers make level design, for example, this video:
sorry for the poor wording in my previous comment. good luck and happy deving!