Going up from Magatsu Mandala 3 to 4 (likely works in other places), hold down on the control stick and press A to swing the sword as you pass the 4th party member. If you are lucky enough (might take many tries), the camera will go OOB. Continue holding down for a bit and release as the MC appears through the back of the portal. You are now OOB. If you go too far OOB, the game will crash.
I couldn't find this clip mentioned anywhere.
If consistent setups can be found that don't involve the Magatsu Mandala portals, maybe this could be used to skip the Orb of Darkness in Void Quest, the key and backtracking in the Secret Lab and the entirety of Magatsu Mandala.
I managed to walk around a bit more after this, but the game crashed when trying to go around one of the large square rooms.
Edit: I made a youtube video of the clip:
I experimented a bit and it seems that clipping the camera out of bounds is a combination of perfect MC position and camera angle (and maybe the orientation of the portal, I haven't managed to do it yet with the portal facing east or west). When I manage to get the camera OOB I can, for example, walk the camera in bounds and out of bounds again as long as I move the MC exactly up or down. But as soon as I move the MC to side or move the camera I can no longer clip it out of bounds. Once the camera is out of bounds, walking the MC out of bounds is trivial for whatever reason (just slowly move him directly towards the camera, no sideways movement or else the camera will clip in bounds). Once the MC is out of bounds, the camera will happily stay out of bounds.
Update: Swinging the blade may or may not help, but doesn't seem to actually be necessary. If you just keep holding straight down and resetting the floor over and over it will eventually work...
