Killer Triangles

The ancient civilization of Tri Land is under attack by evil Triangles. You are the three-sided hero Tri Land needs to defeat it's Pythagorean foes. Get 50 kills to progress to new levels of increasing difficulty. Upgrade your weapons! Collect power ups! Place turrets! Can you protect the civilians from being executed? Or will you just end up with a hypotenuse around your neck too?