The whole time trial platformer idea is pretty cool, but I'm not so sure I like the "twist". Or maybe I would prefer the invisibility without being timed. It's just that the combination of those factors makes it hard, and not in a challenging way, but a frustrating way. Perhaps you could add more assistance, like clouds of dust that pop up at your feet when you land on a platformer. Because as it's implemented now, there are things like hearing you land that can throw you off if you landed somewhere you didn't expect. Also, the timing is set very aggressively. You seem to base the time off of a speed run when you're not invisible, but when you are invisible, it can be really difficult to know how far you are from a ledge, for example. Another problem is that the jump key is just not always responsive. The jump needs to really be on point if you want people to speed run while invisible. They need to be able to queue up jumps as they're about to touch the ground. Right now, there are times when I try to jump, and it just fails to register and I fall off a platform. It just feels like you're trying to make a skill-based game, but in the end, there's too much luck involved. Another way to go might be leaning into the invisibility more and focusing on making that fun. Like perhaps you're just invisible the entire game, and instead of being timed, the challenge is learning to do the jumps without ever seeing your character. And that way, at the end of the game, you could have a reward like reaching a machine that turns you visible again.
Overall, the game is actually really fun. The jumps and level designs feel really solid. Good basic platformer. But the combination of factors contributing to difficulty makes it maybe a little too challenging for a lot of people.