Metal Slug - Zombies is a gory shoot ’em up game. You must defeat endless waves of zombies, who will try to kill you with their bare hands. You can move faster than they do, and you can use your dagger or your pistol to attack them. You can also set mines to explode when the zombies touch them - use them wisely, otherwise you will run out of them very quickly. Keep in mind that you must be far from the mine when it explodes, else it will damage you as well. As bullets will go through the zombies, if two or more of them are in line, you will be able to kill all of them with just one shot.

While you go up from level to level, new enemies will appear. Some of them will be stronger or quicker than the previous ones, so defeating them will be harder. As you score points, you will be able to exchange some of them for some enhancements for your commando - you will be able to increase his headshot ratio, and your gun and knife damage and power.

The game can be played in two modes: Nightfall and Midnight. "Nightfall" is easier, because zombies will come from the sides only, while in "Midnight" they will attack you from anywhere.