The Killing Floor is a field trap that damages foes walking over it. Can hit several ennemies but discharges and has to reload after every attack. Overall nice item to complement your already wide array of weapons.

Sanctum: Killing Floor one of my favorite DLC towers/traps. This is a floor base towers which damages creeps when they step on it. Think of it as a laser (OMG LAZOR) mine/claymore type thing. There's a lack of floor tower in the game so this is really nice. I like to do a slow field, killing floor, Gatling combo to take out early round creeps, than add in some Lasers. All and all, A good day for you, a bad day for them. Note: if you are wondering you just get a key to enter into your steam client to unlock the DLC.

The 'Killing Floor' is a kind of situational weapon/tile. If you are on a map with no flyers then it is a viable option but the slot it takes up can often be vital in fending of flying creeps.

To its defense though, it DOES deal large amounts of damage (especially when upgraded) to land creeps and being that it is a tile, it can be a very useful addition to any maze that needs to do that much more damage.