...alright!!

A little shadow added to the back buffer, and everything scaled so that the gameplay fits within the alcove.

-=-=-

Scaling the sprites was insanely hard, but it seems to be scaling nicely to any given resolution/ratio.
The two pickups at the bottom are going to look a little offset, due to the front walls not quite showing up in all resolutions. (On a tall, thin, portrait view, you can barely see the front walls at all.)

..but otherwise things should more or less function well enough to be playable.

Next is coding the actual gameplay.
Eeek!