(from the main site)
Soldat is a unique side-view multiplayer action game. It takes the best from games like Liero, Worms, Quake and Counter-Strike and gives you fast action gameplay with tons of blood and flesh. Soldiers fight against each other on 2D battle arenas using a deadly military arsenal. This is what multiplayer was invented

Most important features:

Game environment based on real physics rules
Over 18 weapons available:
- guns like MP5, Ak-74, M79, M249 Minimi, Barret M82A1, XM214 Minigun
Multiplayer network game over the Internet or LAN
Intelligent bots
7 game modes:
- Deathmatch
- Pointmatch
- Teammatch
- Rambomatch
- Capture the Flag
- Infiltration
- Hold the Flag
42 different maps
Editors: Soldat Map Maker and Interface Maker
Lobby server and dedicated server for Windows and Linux

I've been playing it for a year and i think its still the most addicting multiplayer game on the web.

http://www.soldat.pl/

Its free to play but you can pay a one time fee of $9 for some great xtra features.

Screenshots:







WIki:http://en.wikipedia.org/wiki/Soldat

You can tell by the screenies how frantic and crazy this game can get.

At first glance, it kinda looks like Lode Runner with guns. I bet it's nothing like it, though. Does look interesting.

I have played it before at a friends house. Very frantic. I recommend checking it out.

Very frantic and fun game. Especially fun if you're playing with a load of friends. Becomes a pain at times online though because there are so many exploits and so many hackers. But all in all quite a fun game to pass the time with.