Well, I feel shame for ultimately picking a room-escape variant, but the current idea is to use room-scale VR to have the player explore a maze of portals within a 2m cube:

(labels: Down, Left, Right, Up, Front, Back)

Each button enables the portals of that color and disables all others (so they create a progression of three overlayed mazes). Each portal is placed on the floor as a 0.5m square within a 4×4 grid, which can be irised open by touching it with either hand. Players can activate an opened portal by standing over it, causing them to fall back into the room through a hole in the new orientation’s ceiling.

Now… to build it!