I beat that level by building LOTS of arrow towers (thanks berserker, for that tip...I'd been using a variety of towers, with no luck). I put about ten of them in the two corners from which those little statue things pop up, and just kept repairing them as needed - while I continued to build my camp.
Now here's the
real trick to beating that level...I used FOUR temples! Yep, I had to tear down some of my buildings, but since I wasn't using any towers that needed the laboratory, I tore that down as soon as I'd done the research (just in case). Ditto the sky hall and the hall of mysteries, I built them, did the research, and demolished them to make room for other things.
Ultimately, I ended up with
four temples, three each barracks, archery ranges, and caves (just cuz I like those rough n rugged cavemen

). I had about
12 to 15 shaman tents, 2 - 3 witchdoctor shacks...and
LOTS of towers. Anywhere I could squeeze in a tower, I did. Oh, I also put another group of towers by the "exit", hoping to catch those statue creatures when they tried to sneak into my camp while I was busy fighting the big statue - though I'm not sure it worked. However, with four temples, I was able to keep
something charged all the time (mostly storm and meteor showers) so I always had an edge.