Hehe, neat! I remember doing something similar, albeit once accidentally. Instead of changing the shell (e.g. to LiteStep), I forced an old DOS game to be executed before windows. Exiting the game would result in shutting down the PC.

I was terrified that I removed my OS and replaced it with a shareware point and click adventure game.

It was a great learning experience though (esp. for my German: https://moorhuhn.fandom.com/de/wiki/Dunkle_Schatten)