alt Hacker NewsI always wondered how NES games, which were notoriously low memory, could have game simulation on the start screens. Think Super Mario Bros, but there are many others. If no input is received at the start menu, the game starts playing a demo run. You always see videos and posts about how developers were dissecting sprites and swapping color pallets to work around the small memory, so how in the heck did they manage having the gameplay demos?
The demo playback on 8-bit games was rarely more than a few seconds long, and it's just a capture of input data.
Here's Super Mario Bros's demo replay data: https://gist.github.com/1wErt3r/4048722#file-smbdis-asm-L108...
21 bytes of joypad input and 21 bytes of input timings