There's not a lot of backstory included in this 2D platform game, but apparently we're working for the Zombie Smashers, who assign jobs and pay cash money for (duh) smashing zombies. The demo begins with a quest to save little Missy from zombie dancers at Club X, and there are a variety of other quests to find in the one provided area (the full game has four).
Gameplay consists mostly of punching, kicking, running, and using objects scattered about the playing area. In order to defeat the bosses, it's crucial to grasp the concept of throwing projectiles and running. Unfortunately, a slight bug makes running a bit more complicated than necessary. (To keep running, press forward twice, then hit up or down quickly, while holding onto the forward button.) Zombie opponents rise in difficulty quite quickly, but if you gain enough money smashing them, you also can add special attacks to your arsenal. Corner stores offer conveniences such as milk, malt liquor, and beef jerky, all of which improve your various attributes like strength, melee ability, and maximum high points. Various eateries along your journey will restore your hit points via fried rice and explosive burritos (all for a price, of course.)
The soundtrack for Zombie Smashers X2 includes mostly ska, funk, and punk tunes, but if your musical style runs contrary, you can listen to your own songs by dropping them into "tracks" folder in the game's directory.