ShootMania is a multiplayer-only FPS that tries to also be an MMO/RPG of sorts. With a leveling system that rewards kills, surviving longer than others and wins with points that can then be turned into additional shots, quicker reloads, armor and so on. In ShootMania’s BETA, you have access to 2 game types with “Royal” (Free for All) and “Storm” (Capture the Flag).
One Angry Gamer "Now here’s a bit of news you probably didn’t see coming: Nadeo has announced that you can gain free access to their ManiaPlanet games right now, no strings attached. You download the free demo and for 48 hours straight you can play the ManiaPlanet titles for free."
Shootmania Platform, developed by Nadeo, will be free in its current beta form for the whole summer.
The Trackmania games rarely go on sale, so getting any and/or all of them is a recommendation.