Welcome to Halo... if the next installment were coded in the early 80s.
A former VP of Microsoft's gaming division took it upon himself to blast everyone into a graphics- and sound-induced fit of nostalgia with this one. It plays like a cross between the old-school Atari games Berzerk and Adventure. Definitely one to check out and get addicted to if you're so inclined.
Click HERE to go to the game
Another screen-cap, exhibiting the awesome 4-bit grafix: