As a kid who loved Kingdom Hearts and The Matrix, I wanted to make a game where you could choose from the standard Magic, swords, guns, OR you could whip out your keyboard and hack the game.
It's not nearly as exciting in retrospect, as it's basically just Skyrim with console commands, but the thread brought it back to me so I thought I'd share. It felt like a cool idea in 2002, though.
I've also been writing and designing a Pokemon game in my head for the last 25 years, but I'm keeping that one closer to my chest even though there's no universe where that happens.