Alien Arena is a First Person Shooter (FPS) done in somewhat of a Quake or Unreal Tournament style.  The entire game is free, open source, and lots of fun to play.  (If you want to see what the game looks like, you can get some screenshots of the game from icculus.org that are a far cry better than anything I could get.)

There are a number of new features that the 2009 version boasts.  Among these are better graphics, a better HUD, and much more.  Several core features have been improved as well, including upgrades to key components such as OpenAL, addition of Ogg-Vorbis support, and much more.

The game opens up to a standard startup menu, with single player, multi-player and more.  Single player drops you into a rotating set of maps that range from a space station to a ghost town.  The weapons in general are interesting.

And I use the word interesting very loosely.  The default weapon, some weird energy ball gun thing that shoots green plasma balls, is about as anemic as weapons get.  The default weapon in Quake and UT were more powerful than this thing.  Plus the whole “pew, pew, pew” of the gun gets a bit annoying.  You'd figure for it's size it'd have more punch.  Nope.

Now that's not to say you can't do some damage with it, because if you play it right, you can take out a lot of people.  It just takes a while, and by the time you get 25% damage on your enemy, he's likely run you through the grinder a half dozen times.

Another weapon that's good is the flame thrower.  It's short range, as is expected, but downright effective, much to my pleasant surprise.  But for real fun, the grenade launcher (aka Smart Gun) is worth having.  It's very unique in many ways, and while it's got similarities to other grenade launcher weapons, the resulting explosion is not.  It's like when the grenades go off, it lays down an EMP field that will mess up your world something fierce.

The beam gun, aka the Disruptor, another weapon in your arsenal, works pretty good, but is somewhat hard to aim accurately.  The chain gun works really well too, but feels more “spray and pray” than actually practical.  The rocket launcher though works well and does a good job “spraying” your opponent all over the map.  ^_^

And last but not least is the Vaporizer/BFG.  One shot, guaranteed kill, period.  It's a very hard weapon to come by, but you can't deny the results.  Another weapon, although even harder to come by than the Vaporizer/BFG is the Violator.  It's also a guaranteed kill weapon.  Just don't ever use it unless you really feel suicidal or just want to be the alien equivalent of the Kamikaze.  

I say that because you have to be at point blank range to use it.  It's kinda like a knife in gun form with a nuclear option.  Very effective, guaranteed instantly deadly, but near on impossible to use without being smeared all over the map every time you get close enough to use it.

Another bonus too is that every weapon has an alt fire mode.  It depends a lot on what the weapon is as to what it's alt mode is.  These guys here have a great guide with a lot of detail on all the alt modes and features of each weapon.

Now, while these weapons are fun to use, there are some issues with them.  While accuracy with the weapons is better, it's still lagging behind.  There are plenty if times you could point dead on at your target and still miss.  It didn't happen all the time, but I got used for fertilizer plenty of times because of that little glitch.

As for the graphics in the game, they're definitely better than they used to be, and the speed is noticeably better as well.  No longer am I seeing my machine dragged down into heart attack city just trying to play the game.  There's still lag that you can see (not internet lag, but actual game lag), but the amount of it is considerably less than it's ever been.

The maps that are included in the game are a ton of fun, well thought out, and generally a lot of fun to play.  The AI's have also shown a marked improvement.  Unlike before where the only thing that gave the AI's a fighting chance and made them interesting was the faulty weaponry that hamstrung me during gameplay.

But now that they don't have that advantage, you would think that playing single player would be a lot easier.  Nope.  I got used for fertilizer just as much in this version as in the past.  The only real difference, other than the improved weaponry, that made the difference is that the AI's are smarter.  A lot smarter.

I'm a man who tends to find a system and work it when battling AI's.  In a lot of games, once you figure out your system, the AI's become rather boring because the game quickly becomes a one sided slaughter fest in your favor.

Not with these guys.  Sure, they still had a few minor weapons glitches to their advantage, but they also adapt well too.  Everytime I got my system figured out, they'd throw a monkey wrench in the gears and set me back to square one.  I have to say I enjoyed that.  It kept me guessing, which made the game even more fun.  

Multiplayer works well in general.  It's very similar in many ways to single player, only your choice in cannon fodder is decidedly human, rather than mechanical, so you need to play a bit differently.  The game also handles lag issues pretty well.  Some work could stand to be done in that area to smooth the jumpiness caused by lag, but overall it wasn't bad.

The settings in the game are also pretty easy to work with.  I found the game to be very stable, very easy to work with and a ton of fun.  It was a little slow going between major areas of the game (IE, between gameplay and options screen.), but otherwise I really didn't see any problems.

I would gladly give this game one and a half thumbs up, leaving off the other half a thumb for the improvements the game still has to make.  But even though it's only got a little bit to go before I'd consider it “ready for primetime” quality, it's still a very fun game and has definitely been showing improvement time and time again with each version.

If you get a chance, download a copy and take it for a spin.  It's lots of fun and you won't be disappointed!