“It also runs on a RP-Pico with only 264kB available RAM!”
Potatis passes every 6502 CPU test, illegal opcodes included, and ships NES-as-a-service over netcat with ASCII, Unicode and Sixel rendering. No client, no account, no subscription. On a Raspberry Pi Pico it went from 0.5 FPS to a steady 5 FPS with overclocking and the second core. Clientless cloud gaming turns out to be a few ports and a terminal.