I think many noticed already, but in 2chd's prototype, when you enter the cogs room, try running or flying. Yes, apparently there are 4 layers. My deduction is: Layer 1=FG, Status bar and the cogs BG=Layer 3 and Layer 2(the remaining BGs)= 2 layers? huh?
No, not 4... 5 layers, 3 of them are actually layer 2, but coded very different from any SNES game. In fact, I think this is the first time I see such a thing.