Very enjoyable fight, they used limited resources in a very creative and effective manner, solid strategy always beats dump strength.
Also, can't they just cave in a lump of sand on the monster army itself? cornering monsters sounds good and all, but removing the path of retreat means also that it will be a fight to the death, being able to alter terrain should be amazing with pikemen if you have a way to defend the frontlines from spells or massive enemies.
Feliprins1