Funny, I’m in the process of selling much of my Computer Reset pickings for cheap, including my 486DX4 100MHz that I ran Mario 64 compiled for DOS on. It ran at a blistering 3 frames per minute.

I’m leaning toward a short somewhere, since you said the PSU starts up with the paperclip but not when plugged in to the board.

The assets aren’t free and open source. If you want to legally use the open source code to play a game, you’ll either need to buy the game to get the assets or use an alternative like freedoom.