Would help to have some sort of indicator of what % of max total ammo is filled for each gun.
Also a Perk / Level up system would make things more interesting.
Got Brilliant on 14 and 15 finally at level 30.
For level 14: A) Have maxed out AOE Temple on the high points by each entrance so it is the first to hit enemies. B) Put leveled up crit strike dens on the high points by the gems as well as well as along the sides (where they can cover both the gems and the opposite entrance). C) Max out mana pool, and both meteor skills.
Level 15: http://imgur.com/6zv1w
A) Start off by building orc dens and a pair of temples surrounding the gems with orcs on the three lower high points. Let these towers level up a bit on early levels. I would leave the snow mana point alone until later. B) Around level 10, build AOE temples at the top left and right corners and the top high point.
You want to allow the towers around your gems to level up early so they are able to take out ninjas in one salvo once they reappear. Save up mana for meteor and try to max out the temples at the top of the screen by level 40 when the ninja champion appears.
On lvl 8 just build a natural gas plant and a lab to upgrade it asap. By the first night you should have also built 2 farms, a factory + dump+trucks, 2 mines , and at least 5 each of lights + turrets. Your 25 gas should last you until after the second night with plenty of power and enough time to switch to nuclear.