Very impressed by this abstract approach. I wouldn't have thought rendering all the walls in the same flat colour would work... but it does. I guess the brain magically fills in the details.
Having rooms rather than just corridors made navigation more memorable, so I didn't need a map. This is something I'll bear in mind for own game(s).
Didn't get too far in the game (got my ass kicked after the purple door!) but that's down my lack of playing experience.
PS Ran fine in Wine on Linux.