I've spoken to the elders of the Rock Monster tribe. And they've come to a consensus as to which entry was best suited for their guerilla warfare tactics. This was a tough decision as there were two outstanding entries. In second place:
The Rocck by Puddleglum
And in first place:
Boobytrap Bridge by BrandonB9
These two entries stayed true to the guidelines of the contest. The idea was to keep things simple and have some element of a surprise attack. Complex machinery and technology are foriegn to their heritage and way of life, and thus would have a difficult time gaining traction in their strategies for revenge. The rest of the entries were great as well. Ry's pick for third place was Larry Lars' vehicle. My third place choice was a tie between Skafte's Lava Ambush for staying true to the guidelines, and Hugobax's The Shredder Truck for sheer looks. The only reason Boobytrap Bridge took first place was the inclusion of video to show the explosion. Had Puddleglum been able to pull of a spring loaded blade that pops out and rolls, it would have been a no brainer.
Thank you all for participating in the contest. It was a real treat to see all the entries in support of the Rock Monster's efforts to defend their land against the invaders.
(BrandonB9, send me a PM with your mailing address. You have a boulder blaster headed your way.)