In the scene where the Zombiemaster is looking at his creation through a mirror, director Jonas Wolcher originally wanted to use an 80's "Snoopy"-mirror owned by Mathias Engman (Goon 2). However, on the day the scene was shot Mathias forgot to bring it.
Goon 1 has a mo-hawk in the first scenes, but in the later it has disappeared. The Zombiemaster emphasizes this by running his hand over the top of Goon 1's head in one scene.