And here is the cardboard room working in game!
Even after a lot of painstaking photoshopping to make everything line up, somehow there's a weird visible seam/misalignment with the top wall. I'm pretty sick of that photoshop file for now so I'm leaving it as is. Even with the ugly programmer art on top, travelling through the doors conveys depth, and really makes it appear like the objects are in the space and travelling through the door. I'm still debating exactly how much animation I plan to do for this project. The character really needs to move smoothly for visual clarity, but I don't know that I'll do anything too fancy with the room transitions. We'll see though. Next step is replacing that programmer art before creating smooth animations.