Very simple, somewhat fun. The best bit was when Anarki and I collided over the RA spawn and both ended up on top of the central pillar structure. Great place to rail from...until I rain outta ammo and ended up jumping into the pit since I couldn't do anything :-)
Good idea, just try it a bit bigger! You've got the artistry down clean, and the gameplay half way there with fairly innovative ideas.
P.S. Gave it an 8, I luv my railgun