Lego has had a couple Alien/Space themes. The last one Galaxy Squad had an alien menace that was more insect. Alien Conquest had a more little green man theme to it. I'm not sure where this alien fits in, but he's got a great head sculpt and some really printing on both the torso and legs.
I also really like the florescent disc on the gun. When it's in the sunlight it really looks like it's glowing.