I guess it's $15. Played it a bit tonight with Gene. Seemed like fun. It's way different then your normal run-of-the-mill run-n-gun games we're used to. It's space, after all. You spin, float, etc., etc. And where we're used to a sorta 2D-type warfare (almost everyone's eye-level with you), this is a very 3D-type warfare where one enemy could be right over your head while another is right under your feet.
Anyway, it seemed like fun and for $15 it's a decent distraction from what we're used to.
I sent one invite to Pete and another to Gene. I have one left and with Shakes having three, four more can try it out.