Zombie Defense features an open-world gameplay experience where players must defend their position against relentless waves of undead creatures known as "zombies." The game allows for various weapons to be used, including guns with different abilities and upgrades that can increase damage output. Players are given a limited number of rounds in each wave before the zombies take over. The objective is simple: Defend your area from zombie onslaughts while trying not to get hit by their bullets or other projectiles fired at you during waves 1-5, which have higher probabilities for hits and more frequent updates on player health.
The game offers a variety of weapons with different abilities that can be used in each wave. The zombies are relentless; they move faster than the players but also attack harder as time progresses due to their increased speed over enemies who take longer periods between attacks or waves 6-8, which have lower probabilities for hits and more frequent updates on player health.