yea, i really agree with the pain points here. so uhh i did NOT code the game perfectly. as you correctly assumed, gravity is kinda screwed up: each planet has a predefined "gravity radius" that flips the player's gravity when they get into the collision box. the problem is that the radius in which you reverse gravity is unfortunately arbitrary so it can feel more or less lenient than expected sometimes. i VERY agree that a light ring around gravfields would have been an excellent visual hint (and I was considering as much, but for some reason didn't get to it). not only that, but a visual indicator as to which was moves you left-right with an arrow (sometimes left is right and right is left: even I never really got it 100%)
preserving the player's velocity vector would have been difficult on gravity flipping: the vector used for preserving speed is different from the ACTUAL vector that gets used for doing movement calculations due to the way I had to kinda work around Godot's pre-existing cartesian calculations. therefore, i did the thing that gave me the least amount of headache and just zeroed each velocity vector on flip.
regarding the super speed level: ceiling bonks are the real reason why its a bit screwed up. you transmit a lot of vertical momentum downwards when you bonk into the ceiling (-0.7x your current vertical velocity, shoulda been more like -0.5x or lower). so, actually NOT holding jump and simply mashing up 2x to jump through those inner pits allows you to not bonk your head as hard (because you have less vertical momentum).
finally: you absolutely do NOT have a skill issue (nor does anyone else whose played it). the game is very much a masocore rage game. i should have been more clear that "yes, this game is very hard and you will die a lot".
i plan to make at least one more update to this game after the jam's done, so your feedback is VERY helpful! thank you so much for checking the game out : D