Does it have onboard graphics? It will be hard without that.
If it has, you can make a vintage arcade machine, but with multiple games. You could, for example, run linux with OpenTyrian on it, which is one of my favorite games. Xgalaga++ and a lot of old games with DOS emulation should also be possible. You can strip down the OS, so only the barest minimum runs; should save some RAM and CPU.