from their site:
As was utililizing cutting-edge technology for PARABELLUM, we at ACONY felt it was also very important from the start that as a free-to-play game, PARABELLUM would run on most machines; not only state of the art hardware. ACONY did not want to compromise the quality for which FPS games are known. Considering all of these factors made the decision to implement the "Unreal Engine 3" technology an easy one.
Doesn't seem too bad, but its all instanced to a max of 20 people per server. Not quite what I'd call "MMO"