Warmonger: the game

http://www.warmongergame.com/

This is a F R E E game. It can be played online or in offline "training" mode, and it freekin ROCKS!!! :dood I've been playing it off and on now for about 2 weeks and it's insane. It's fast and furious, and HARD! If you're into shooters, fast & difficult shooters, then this is for you. And it's totally FREE!!! Be sure to disable your antivirus/antispyware software when installing. I didn't at first (MalwareBytes kept flagging something) and apparently the game didn't install correctly and it kept locking up about 3-4 minutes in.

(once I realized that the weapons will destroy things you shoot at, it really changes things! If you have a chaingun or assault rifle, and you hold the trigger and start blasting a wall, it will break into pieces like a real wall would. This also allows enemies to blast at you by shooting a wall to smithereens!)

EDIT- the game requirements are fairly high; not by todays standards really, but if your hardware is more than 2 years old, you may have lag or other issues:
CPU: Intel Core 2 Duo Processor E6400 (2MB L2 Cache,2.13GHz,1066) or equivalent
RAM: 2GB RAM
GPU: Nvidia 7900 graphics card or equivalent
PPU: PhysX 100 Series Processor strongly recommended, with system software 7.11.13 or later
HD: 1.8GB of available space
I'm running an AMD64X2 5400+ @ 2.8ghz, 3gb DDR2, Geforce 9600GT @ 720mhz/2ghz and I have zero lag...