Hi there!
Battle Bruise is built on top of the "Atop a mountain of corpses" trope.
Behind the scenes, each dead body is a painted skeleton on the terrain mesh, and the mesh itself grows a little where this body is. When a lot of dead corpses get together, bigger and bigger piles shows. It also changes a 2d tilemap, used for movement and bullet hittesting.
Ironically, the game is made on the K.I.S.S principle (Keep it simple, stupid), but, almost every movement and hittesting of the game is handled by our code. There's, at the maximum, the use of physics.raycast for bullet x enemies hittesting. Everything else is home made.
These crazy and messy blue/orange lines are part of our debug routines, most used for visualization of the movement algorithm. We're using most boid movement for the swarm. There was a layer of A* before, but it was commented out, because it was kinda useless (boid seek works quite well for now).
Well, that is it. If someone have some question, sugestion, or anything else, please ask. I love to talk about such things.