Known glitches:

For any% and 100% 9: YamCider found that the red barrier can be clipped through. It is very precise (frame perfect?) but it seems to involve, when jumping off the platform prior to the barrier, jumping very late (when it actually looks like the character has already gone beyond the edge of the platform) and only soft tapping jump. Then, when the character comes back upwards, push right and the character should clip through the barrier at the top.

For 100% 5: To get on the ledge above the red barrier you have to double jump off the first platform. You can then simply double jump over the wall (off screen). 12: Jump to the furthest upper block for the pill, then single jump off that block and pull right as you drop. You can then walk right (below screen) until the level is cleared.