I think that you accidentally made a rage game (or maybe it wasn't so accidentally after all??)
The gravity switch mechanic was hard to get right (it is not really responsive) but overall if you want to go for the rage game genre, this is perfect haha. I definitely see speedrunners try to beat this game :]
Further, jumping wasn't really required, but holding on to a wall definitely was useful!
(small tip: make credits move from top to bottom rather than from bottom to top)
Overall enjoyable game to play!