I've compiled a small list of tricks that can't be used yet but could have potential use if someone can do something with them.

Level 20 gap skip without using beast mode: This could possibly be used in impossible runs since farming beast mode takes forever on impossible.

Going out of bounds in level 2: Level 2 is connected to level 14 similarly to how level 5 is connected to 16. I couldn't actually do anything with this tho.

Going out of bounds in level 4: Couldn't find a way to go back in bounds.

Climbing the mountain in the first part of level 20: If you can skip the part where you're trapped by fire in the tunnel, you'd save a lot of time but i couldn't figure out a way.

Climbing the mountain in level 12: If executed perfectly this is actually a small time saver in the all levels run. You can get to the other side of the river with this too but you're a bit stuck behind trees and can't exit the level.

I found an interesting glitch involving doors. While in first person, hug a closed door that opens towards you, open it and then close it and spam jumps while it's closing. This will throw you upwards a bit and clip you through the ceiling. I only manages to find 2 uses for this since most doors don't throw you high enough:

I noticed people complaining about this game crashing, i had the same problem when playing it casually and running the sequel. I managed to fix it by setting core affinity to 1 core in task manager, hope this helps people. (windows 10)

I've tested various movement types to see which one is faster 1st person run 3.87s 1st person jump 3.15s 1st person roll 4.14s 3rd person run 3.52s 3rd person jump 4.41s 3rd person roll 3.02s insanity 2.81s Tests were done over the same distance. 3rd person rolls seem to be the fastest but 1st person jumping offers way better mobility so it's likely the best one to use in most cases.