Seems like you’re describing something like Pico-8: https://www.lexaloffle.com/pico-8.php https://www.lexaloffle.com/pico-8.php There are also open-source vers

Seems like you’re describing something like Pico-8: https://www.lexaloffle.com/pico-8.php https://www.lexaloffle.com/pico-8.php There are also open-source versions of the concept, like TIC-80. The only thing missing is upgradability.