As if that's not challenging enough, recall that the game Elite [1] ran on a BBC Micro (model B), a computer that also used the 6502 yet had only 32K of RAM, half that of the C64! It still blows my mind how they were able to accomplish so much on such a limited computer! [2]

[1] https://en.wikipedia.org/wiki/Elite_(video_game)

[2] https://gdcvault.com/play/1014628/Classic-Game-Postmortem