With its overhead perspective and constant swarms of enemies All Zombies Must Die resembles old dual joystick shooters like Robotron or Smash TV. That's not how it plays, though. As in most shooters you'll attack with the right trigger button, switching between your gun and melee weapon with a quick press of the bumper. There are a variety of both types of weapons, but you can only keep one of each at a time. You can also use your fists instead at any moment, and they're very often the best option, at least early on. Fists are faster than the first gun you find and do more damage than your first melee weapon. Later on you unlock a limited edition, single-use smart bomb that wipes out every enemy on the screen.
Each area is basically a self-contained mission. Most missions don't take long to complete, with simple goals like finding a specific item or killing a certain number of zombies. The game only saves when you move from one area to the next, though, so if you grind or take the time to find every searchable spot in an area, and then die before moving on to the next, you will lose whatever experience you've earned.
There are characters. Sometimes they talk. Ignore them and their words. There's nothing funny or likable about the first two, a pompadoured "gamer" and his shrill and hateful ex-girlfriend. The banter of the talking robot gates that sequester each area is occasionally funny, and the lead's encroaching awareness of being a video game character is a nice callback to the meta wackiness of old cartoons, but the character designs are bland and the characters are generally unlikable.
The early weapons have a few kinks that limit their usefulness. The shotgun has a wide spray and inflicts great damage, but without patience or a lock-on option you'll often waste ammo firing in the wrong direction. You need to make sure your character has turned and is directly facing your desired target before firing. Multiple times I'd hit the joystick towards the left and hit the fire button a split-second later, only to see my buckshot fire nowhere near the zombies bearing down on my left.
The first melee weapon unlocked is a cricket bat. It has a wide, almost semi-circular arc, hitting basically any enemy immediately in front of you. It does surprisingly little damage, though, much less than your fists, and thus can be frustrating to use. Somehow it's less effective than those fists.
The combat might be basic, but light RPG elements add a bit of depth. You earn experience for each kill and for searching through various objects like cars and file cabinets. Eventually you establish a home base in an old police station, at which point you can cash those experience points in and beef up your attack, defense, health, or speed. I can't tell how essential it is to level up your character, but at least it gives you something else to think about beyond brainless killing.
All Zombies Must Die isn't groundbreaking, and I personally find its aesthetic to be a little annoying. Still, there's a solid chunk of arcade-style fun at its core, and the couch co-op helps mollify whatever issues I might have with the game's style.