This is a really solid start, especially for a first game! I do wish there were more levels, though… the last level was both unusually easy compared to the one just before it and didn’t use the flipping mechanic at all, and then the game ended unexpectedly. Nothing wrong with a short game, of course, but I think one final level to test the player’s skills might help the ending feel less abrupt. Additionally, though this is a small complaint, the “FLIP” prompts are probably unnecessary past the first level, since the player probably understands the mechanic by that point.
A small piece of advice, though this is somewhat up to preference: I found it a little awkward how all the game’s bindings were on my left hand. Shift to dash especially was a bit uncomfortable for me - it’s common to bind actions to Shift in 3D games, but for 2D games I think having actions controlled with the opposite hand as movement is more ergonomic. Perhaps J/K could be used for jumping and dashing? The common arrow keys + Z/X scheme could work as well. Just a thought.