Vortex is an Action-RPG for Quake 2! The first playable version of it was release in 1999 and here we are, 10 years later, still around thanks to continuous updates, improvements, and a strong fanbase! Kill monsters and players to gain experience points, which learn you levels. You are rewarded with ability and weapon points. Use these to purchase some unique abilities and upgrade your weapons! Become a tank, spawn monsters to fight for you, or deploy devices to aid you in battle! With over 100 abilities and 10+ different classes to choose from, there is NEVER a dull moment in Vortex.
Here's a screen shot of me camping with another Necromancer. Each of us has 3 monster slots. Tanks occupy 2 slots, while medics take 1. The tank + medic combination is effective, because the tank can absorb a tremendous amount of damage, while the medic sits nearby and heals him.