After watching the Mario movie with kids, i dropped original NES Super Mario Bros on them. They enjoyed the new (to them) gameplay, while marveling at the limitations: you cannot go back? With me remembering a surprising number of secrets, i got a bug in me to revive this ancient trick. Unfortunately, i wasn’t able to get it working correctly in the limited lives i had. Undaunted, i finally completed it just a few days later while waiting on an OS upgrade.
my favorite part was that it overflowed the numerals and became pictures when displaying the remaining lives. if you got too many extra lives, it ended the game.