I think that FOSS games are cool and can often have better hardware support and modding communities, but they often seem to focus on being FOSS rather than being a good game. However, if you can avoid that, making your game FOSS would probably be a good choice as long as you aren’t trying to make heaps of money. Some other FOSS games that I like are minetest and veloren, and classicube is also pretty cool.