I came across this game which is a first person shooter. The game is basically a war simulator & it succeeds in that area. The mission is to defeat the red team with highest score. . The player is blue team (can be reversed)
I tried the beta 5 which has two maps. Both are great. Now, The game is now available on steam for purchase. But, you can try the beta 5 version from here for free
Its available for Linux, Windows & Mac. I'm impressed with the download size. Its just 80MB !