Ok so, a couple issues with this:
First, the timer doesn't really change anything. It's mostly a waiting game.
The controls feel slightly off, mainly because there is no... idk how this is called. You'll probably know this from other platformers, they let you jump even if you are slightly off the platform. Also, the player hitbox being a capsule makes the player easily slide off edges, which makes tight platforms annoying.
Third and last point, some powers are mostly unnecessary. The improved movement literally has to be used the whole time to beat the level and the invisible platforms can be guessed from the level layout.
Now, I know this sounded bad, but there were some enjoyable parts! I really liked the gravity switch and "blackout" levels. The concept is really good and especially the gravity switch works a charm with the timer. A speedrun-like gameplay approach would really make those shine, not focusing on beating the level but rather on mastering it.
All in all, there is room for improvement, but one half of the game turned out to be pretty fun! Nicely done for 48h, considering how many different levels you made and that you worked on the music too.