What you're thinking of is CHIP-8[1]. PICO-8[2] is similar in spirit, though much more powerful. It's a constrained (in memory, code size, and cpu cycles) lua environment tied to a 128x128 16 color display.

[1] https://en.wikipedia.org/wiki/CHIP-8

[2] https://www.lexaloffle.com/pico-8.php