When something is highly used by a gamer of lesser skill, because it makes them seem better. Normally a rocket launcher or large machine gun will be praised by these said players, which are called noobs,
and so, noobtastic.
The chainsaw action in Gears of War is noobtastic.
The auto-shotgun in Counterstrike is noobtastic.
The rocket launcher in Halo 2 is noobtastic.