Facial Recognition by Al Jarnow, 1978. “The stop-motion short Facial Recognition demonstrates image resolution as kids build images of a familiar face with more and more dots.” Jarnows animations were used by PBS and Sesame Street. source
Owata 人生 オワタ- a game in Shift-JIS ASCII by IlIlIlIlIlIlIlIl, 2008. Play it online here.
TextFighter, an Apple II-game by Bret Victor, 1994. “A full featured arcade-style fighting game that uses only text characters and runs on any Apple II.”
A teletext game for the BBC Micro called Flowers of Crystal (1984). Great intro!