Decay is a Test Map which is loosely based on Thar but built with wider ramps. Unlike most other traditional maps, Decay is designed with each fortress in opposite top right corners, with a large void separating them, making it asymmetrical.
The entire map is tinted neon green to give the effect of a nuclear waste land.
Most of the map is covered in neutral Balooms to deter early game harass and cheese. They can be corralled and flown into enemy mechs for instant death.
There is a debate as to whether the left or right side is superior because it is asymetrical.
The game usually revolves around the fight for the bottom middle outpost because it gives map advantage as well as an outpost boost. A riskier strategy is to bypass the bottom outposts entirely and send a push across the barren middle towards the side outposts or the fortress.