That looks like a 1999 PowerMac. I knew how to network that era with a PC but I don’t really know what games would have even worked on it.

Same, I was networking games with PCs from about 1997 with friends at school. I didn’t get in to Apple until 2005, so I also don’t know how easy it would have been. There really weren’t many games around tho, Unreal Tournament would’ve been the big on cross-platform I think?