Skezlarr

For anyone who's interested, there was a movie made that was loosely based on this story called Oddball: https://m.imdb.com/title/tt3401748/

Not sure how to help you out with it, but you're at least not alone. Robert Smith from The Cure had the same problem with the song "Friday I'm in Love": https://en.m.wikipedia.org/wiki/Friday_I%27m_in_Love

"During the writing process, Robert Smith became convinced that he had inadvertently stolen the chord progression from somewhere, and this led him to a state of paranoia where he called everyone he could think of and played the song for them, asking if they had heard it before. None of them had, and Smith realised that the melody was indeed his."

I think it's Gen 6 (PS2/Xbox). But at the time the Gen 6 consoles were new, the Gen 3 that you consider retro was about 20 years old, just like these consoles are now. I think they still fit the label of retro pretty well, but it's always hard to consider something newer than your childhood as "old" tbh

Backpack Hero gets close to that in a rougelike/lite kind of way