I've found a new possible route on Cellar Zombie by using the ragdoll respawn glitch. With good timing you end up under the yellow ramp at the start of the level, then if you ragdoll on the left wall, there's a slight (1 time in 3 hours) chance that you get teleported near the spot where you clip your head to the checkpoint. For now it's definitely not viable but I think that with practice it could make sub 15 possible on the level. I'll make video about it later today.

The method mentioned above is horrifyingly random. There's almost no way to replicate the teleportation after the first glitch. Doing it without the teleportation by passing through the walls gave me a 0:24 PB which is too long. I have found another strat that I will explain on the video. Mastering it could surely make sub 15 possible

I think I discovered a new Ben and Ed glitch (I haven't found it anywhere yet). The glitch allows you to teleport in the map but needs to have the ragdoll respawn glitch possible. I'm finishing to edit a full length tutorial on how to do the glitch and with it the new route for cellar zombie.