This deck is designed around dealing direct idol damage using the Watcher's effect, triggered by placing a Mire Curse on it and putting many weak creatures next to it to die.
The way I usually play this is to put a Watcher with Mire Curse in the very middle so there are many available adjacent spaces, then try to put a Scavenger Construct (with or without Animovore) in front of it to protect it. Then I breed Bunnies in the top and bottom rows and I can plop a Rat King on the Watcher to get three rats next to it, or put out Anima Conduit to get extra creatures that can die. Loyal Darkling, Wicked Being, Forbidden Ruins and Totem of Suffering all synergize well with direct idol damage and/or the Watcher. The poison and the Harvesters are there to try and limit the board state the opponent can build. I put Elan Vital in to put on the Harvesters so they can move around the Watcher without dying. Regeniture and Oak Blood are for putting on Bunnies to help against Energy decks, or just on other crucial units to help them survive.