Tower Offence!

The people of the surface and the floating continent are locked in a war over scarce resources. One part of the world is used as a garbage dump by both sides. The protagonist wakes up in that place. She is a prototype of a humanoid weapons system, commonly referred to as a warroid. She knows nothing about the war, being purely a test subject, and so she doesn't know what to do in this wasteland of trash. This is where our story begins.