You may notice a new enemy right off the bat. Astronaut Zombies can be found on the base with names over their heads. Do not get close to them or they will hold on to you, attack you, steal your first Perk, and teleport you. They usually send you somewhere near the start of the moon base. If they do grab hold of you, you can still attack them. Once you kill them, they will blow up and blast you back with a shock wave. The shock wave may kill zombies near by. They have a lot more health than the average starter zombie, so don't hold back.