Found two random glitches while TASing the game a bit.
If you do a 1 frame jump while having a specific Y subpixel value, you clip through platforms that have a 1 pixel wide collision, the arena of Jason Vorhees for example, probably it could happen with any jump height if the subpixel value happens to hit 0 at the right time. Probably not useful for the speedrun, since controlling for Y subpixels seems impossible RTA.
You can jump right after jumping again and gain a bit more height, the most you can do is jump for three frames, stop holding jump for one frame, then jump again.
Not sure if this is helpful, but during the Chucky stage, I feel into the pit around the same time the enemy walked into the pit, and I hit the enemy as I hit the death barrier, which dropped me in from the ceiling. There doesn't appear to be any ceiling mechanic to land on.
