OpenSourceGames

Yes.. to be honest I feel old-school deathmatch arena shooters is the one genre where the FOSS world has actually already taken over what can be found in the proprietary world.

Most of the industry has moved on to some variation of hero-based abilities and/or some form of "mission" objective to try and add more tactical elements that essentially make it no longer the same play-style. Even the faster paced franchises like the modern Doom Eternal have given up on old-school deathmatch.