Oh shit guys! It's a persistent world, with fancy screen scrolling:
Yeah, I need to get those room entrances to move all the way to the first solid, but they are connected and preserved to the random seed for each area. Levels are randomly generated by the starting seed plus their grid location, so saving the seed in persistent data means they'll load up the same every time. There's also a pretty sophisticated 32-bit hash function scrambling adjacent room seeds, so regions of the map don't ever become samey if you hit the same seed in two different games...
The screen scrolling is a fancy memcpy effect of the old screen data to its new position. Since the vertical scrolls only have 14 tiles it wasn't a nice even number of lines per frame like the 16 across was, so there's a little crazy math moving it 3 or 4 pixels depending on how far the next draw will be. Was it worth it? I think so!
Probably my last update of the night, but this has been fun so far! I'll be back for day two after a good night's sleep. =)