The story behind last year's Retro City Rampage is well known by now: programmer Brian Provinciano started the project as an authentic prototype running on Nintendo's classic NES hardware, as a proof of concept that a game like Grand Theft Auto 3 could have existed in the 80s.
That prototype ended up inspiring him to ship an actual multiplatform game which, while a close homage to the system, "cheats" in various ways and does a lot of tricks the NES wasn't capable of. But now that the game's out, Provinciano wondered: could he take the work he'd done and squeeze it back into a genuine game capable of running on the old NES, outdoing his now-ancient 2004 prototype?
The result is what he calls ROM City Rampage, a simple demo showing that a lot of his game actually was possible. In the video above, Provinciano details what he had to do to get the game running on the ancient-but-mighty 6502 processor, how he cut corners to display as large of a map as he could, and what concepts like "bankswitching" and "vblank" mean for those of you who never had the joy of working with old hardware.