PlayOnBSD is a resource for gaming with an OpenBSD focus. (Please check out Links on FreeBSD and NetBSD resources.)
Find out what's available, read about how to download games and learn how to run them.
Some ways to run games are unique to OpenBSD's structure and mission. See Mitigations and Limitations.
Look at Benchmarks to get a sense of OpenBSD's gaming performance relative to other operating systems, and how to benchmark your hardware.