Tremulous is a free, open source, online first person shooter. It began in 2000 as a mod for Quake 3. In 2005, it was developed as an open source stand alone game. By being open source, anyone can use the code to contribute or use for their own purposes. The latest version as of this review is beta 1.2 which was released in December of 2009. Tremulous is powered by the Quake 3 engine and unlike many betas, I have not run into any bugs or glitches. 

There’s no fancy back story or anything to pull at your heart strings; just two teams, humans versus aliens. Each team must build up their base and destroy the opponent’s base. Each side has an offensive class and a defensive class and they have their own unique abilities and upgrade paths.

Upgrades are purchased by the number of kills.  As a team accumulates kills, it allows the humans to upgrade their armor and weapons and the aliens can evolve into tougher warriors.  Builders get points for every two minutes they stay alive.

The alien base is managed by the Overmind which is essential for running and building all of the structures.  Eggs are the spawn point used by the aliens and if there are plenty of eggs, there won’t be a delay in respawning.  There are various protective structures such as barricades, trappers, acid tubes, and boosters that enhance the poison attack of aliens.

Humans must guard their reactor which powers all of their machinery.  The telenodes are used for respawning; again it’s good to be redundant with these.  To protect the base you can install machine gun turrets and Tesla generators.  The Tesla generators will attack any target so you have to set up a defense computer if you want it to attack aliens only.  Armories are essential to upgrade the weapons and the med stations will heal wounded soldiers.  Aliens have the advantage of slowly recovering health on their own.

When it comes to attacking the aliens have melee, poison attacks and the ability to climb and jump off the walls.  The humans get cool weapons like grenades, flame throwers, chain guns, shot guns, and the most devastating of all, the Lucifer Cannon.  The guns require ammo and battery packs and take some time to recharge.  A soldier can wear a battery pack to increase an energy weapon’s charge by 50%.  There’s a jet pack that allows a soldier to fly but they can’t wear a battery pack at the same time.

The game play is pretty fast paced and attacking the enemy base is best done in waves.   If the Overmind or Reactor is destroyed the spawn points will still work but new ones cannot be created.  So to truly win you’ll have to destroy the Overmind, Reactor along with all the telenodes and eggs.  Fortunautely the servers are well populated and it’s easy to find a server with ten or more people on it.

Graphically, well, this game only takes up 125 megabytes and it\'s the Quake 3 engine, so don\'t expect Crysis-level prettiness.  It\'s not that bad though.  At first the aliens look like big spiders(which are easier to stomp) but they do get more intimidating as they evolve.  The humans all look alike, though you can make yourself look a little different if you upgrade your armor.  As a human you see your hand holding the gun like most FPSs, but if you\'re playing as an alien you don\'t see any of your limbs.

I mainly just played on the default map; there are other maps available but you often have to download them at 4KB/sec.  Luckily they aren\'t very big, or it could take hours.  My heart goes out to those who are still bound by 56K modems.

The background music is ambient and not very memorable, but thankfully the sound effects and voice acting for the aliens and humans are a little better.  The aliens sound like the Strogg from Quake Wars.  The guns sound like guns, and the alien screeches and squeals definitely sound like... aliens, so they did a good job with the sounds.

With guns and bloodthirsty aliens, comes violence, blood, and gore.  There isn’t a lot of blood and gore flying when the bullets are, but some maps have blood puddles on the floor.  If you\'re playing on the alien team and you are being shot at there will be a green haze around the screen.  Like many online games, some people will send messages laced with cuss words.  We can only hope that some day the median age of the online gaming crowd rises above twenty-five.

Tremulous is pretty tame when it comes to violence if you compare it to many FPS games out these days.  Granted it can’t keep up with the graphics of modern titles, but the price is right and this will run well on slow computers and internet connections.  It can also run on Linux and Mac OS too.  If you liked Quake 3 or Natural Selection, give it a try, it\'s only 125MB!