In 1992 I built an online multiplayer game called Legends of Future Past. It ran on CompuServe, won an award from Computer Gaming World, and shut down on the last day of 1999. I was 19 when I made it.
The source code didn't survive. What I did have: hundreds of script files written in a little language I'd invented for Game Masters, a GM manual I wrote in 1998, and a gameplay recording from 1996.
I gave all of this to Claude Code without much instruction beyond "figure out what this scripting language does and rebuild the game." What I got back genuinely surprised me.