Hello, the game was fun until the final boss.
Look, I know a final boss is meant to be a challenge, and that a final challenging stretch is to be expected, but combining a tedious final stretch with a tough final boss is NOT a good recipe.
Every time I die, I have to go through that tedious stretch AGAIN, it doesn't help that the final boss can be very trial & error and has quite a few cheap moves. That surprise second phase doesn't help.
I'd say that you either make one of the two things easier, or you put a checkpoint between the final stretch and the final boss.