Description:

Tremulous is a free, open source game that blends a team based FPS
(first-person shooter) with elements of an RTS (real-time strategy).
Players can choose from 2 unique races, aliens and humans. Both teams
are able to build working structures in-game like an RTS. These
structures provide many functions, the most important being spawning.
The designated builders must ensure there are spawn structures or
other players will not be able to rejoin the game after death. Other
structures provide automated base defense (to some degree), healing
functions and much more...

Player advancement is different depending on which team you are on. As
a human, players are rewarded with credits for each alien kill. These
credits may be used to purchase new weapons and upgrades from the
"Armoury". The alien team advances quite differently. Upon killing a
human foe, the alien is able to evolve into a new class. The more
kills gained the more powerful the classes available.

The overall objective behind Tremulous is to eliminate the opposing
team. This is achieved by not only killing the opposing players but
also removing their ability to respawn by destroying their spawn
structures.