I have found 2 glitches so far. Both very hard to pull off, but one most likely being a frame perfect.

The first clip shows the end-flag pause glitch (still workshopping name). This is the one that is most likely a frame perfect timing. If you hit the esc key (pausing the game) right when you hit the end flag, you can trigger the end of the level, and have the pause menu up. You can then skip the end level cutscene and go straight to the level menu, selecting your next level. I am pretty sure it works on every level, so optimally it would be used for every level except the last in a speedrun.

The second clip shows a slightly easier glitch the double jump. If you hit space (jump) twice in quick succession, you will do a double jump. I have not tested as much as the end-flag pause glitch, so I do not know what use it will have in other levels, but for level 3 specifically, it allows you to get the cereal box without slowing down, or going left. It will require more testing, and I will probably post update forums with clips of new strategies and glitches in the future!