Now with levels!

Thanks to a compressed password format and aggressive review of cc65's assembly, SLAUGHTER is no longer a single-level demo! Now there's four!

Also performance improved, diagonals render properly, and sprite projection is much smoother, but that was all in the previous upload. The logarithm tables are quite nice. 35 cycles for A*(B/C) on 6502 still feels like cheating.

Enemy debris now works properly, in a delightfully excessive fashion. Honestly it might get toned down. But at least the kill indicators scale with distance, via stupid sprite tricks. This is an NROM game - there's only 512 tiles. Ironically those tiles are underused for level textures. I have a few decent additions, but integrating them is complex, because I cleverly optimized a bunch of behavior that's now wrong. As you do.

What didn't work at all are the new renderer and mid-frame scrolling. I rewrote the whole geometry renderer to be simpler and more array-driven. It was slower and took more space. Hooray for already being fast and small, I guess. Scrolling the HUD almost works, but the NES is just an awful machine. There's no scanline counter. You get one sprite collision check, and it's not an interrupt. You have to sit and wait. So with the HUD on the bottom, where it belongs, the best trick available is misusing the sound hardware to time out shortly above that and minimize waiting. Or: time out shortly below the HUD and make the first row of tiles boring. I got that working... but then playing real sounds can screw it up... sometimes. 

I am responsible for every byte on this cartridge and an alarming portion of it is straight-up witchcraft to me. 

Fortunately you'll soon be able to help with part of that: levels will be sharable. You can already create levels the same way I did. (It's a lot easier with a mouse - which is also supported in-game.) The inevitable password system will allow transferring those spaces between players and machines... and possibly platforms.