I got curious about how well Nebula can handle DDP3/DDP3Blk (the only Cave(s) game that uses a bios and is emulate-able in Nebula with few modifications).
Anyway, it works pretty well other than problems with the background RAM not being properly mirrored and the sound crapping out.
*Edit* - Fixed the background issues.
The graphics are pretty much perfect now.
*Edit2* - The sound only craps out if you use the turbo function.
To be clear -- I modified the roms, not the emulator (That's why the title bar says Kov). It's a shame El Semi won't release his sources. I'd love to take a crack at updating Nebula.