It looks like the folks over at AAAGames have recently picked up one of my most played games when I was in high school, Tremulous. It's basically a first-person shooter set in a space-like arena (usually, though there are some maps on the contrary), but the catch is that one team consists of aliens while the other consists of humans. The gameplay significantly differs between the two teams, and aliens are especially unique as they are unable to use weaponry (so humans primarily attack from range while aliens are melee). Tremulous also allows you to build structures to assist allies and impede opponents, which is where team strategies come into play.
The original developers of Tremulous have all but stopped development on this game. Due to this, the playerbase has stagnated significantly. A few groups have picked up where they basically left off and started developing new games like Unvanquished and TremZ. TremZ seems to have fallen off the face of the planet now, though, without a release.
Unvanquished is still in alpha, but it is playable and has gained popularity lately. It's runs on the Daemon engine, developed in house as a Quake 3 engine with XreaL features. New models were introduced, and you can also play against AI. It remains open source and moddable. Their forum is pretty active.
AAAGames have also started developing Tremulous 2. It looks like they will be recreating it from scratch on Unreal Engine 3 (the original uses ioquake3), with new artwork. It appears, though, that Tremulous 2 will not be open source or free to play. That personally puts me off from the game, since it basically removes the chance of porting the KoRx mod to Tremulous 2. They also are not going to support Linux, which in itself is a seriously bad move considering the Tremulous playerbase consisted of several Linux users. If you're interested in contributing to it, they have started a Kickstarter campaign to raise money. That page is also pretty lengthy about what they're planning to make.
So, to recap, here are the differences between the two:
- UV is open source, while Trem2 is not.
- Both will be using different models
- Trem2 claims to be like the original (physics and balance wise I believe), UV has made changes where needed. I haven't seen how Trem2 is pulling this off specifically, since it looks pretty different from the original.
- UV uses a combination of ioquake3 and XreaL, Trem2 uses Unreal Engine 3
- Trem2 does not support Linux.
- UV is free to play, Trem2 is not.
- UV is moddable, Trem2 lets you mod skins but not the gameplay.
- UV has a release already. Trem2 has an estimated release timeframe of Q4 2014.
- Trem2 has an in-game shop that handles real money for user-created mods, amongst other things.