Tower defense games (often abbreviated as TD) are defensive strategy games. Players will have to defend their base or territory from waves of attackers (typically called Creeps). Usually, in tower defense games, these attacks will follow a set path and come in waves, enabling the player to place defensive structures along that path. These defensive structures are the towers and will automatically attempt to stop the progress of the assault. Deciding where to place your towers, what upgrades to use, and reacting to the enemy’s progress are all key strategic elements of a tower defense game.

Tower defense games have elements of both turn-based strategy games and real-time strategy games. When preparing for an enemy wave to attack, the initial set-up will let the player place their defensive towers at their own pace. This gives players time to plan their defenses before starting off the game. As the enemy moves along the path laid out, the towers will attempt to defend the area.

Towers will have a variety of abilities. They could have patterned attacks at regular intervals, placed to allow crossfire to significantly damage the enemy. They could also act as turrets, with more focused assaults on the closest enemy units. In levels where enemies can take multiple paths, some towers can act as barricades to their progress, forcing the attack along a path that delivers maximum damage.

Players don’t just sit around and wait for a level to end. As levels progress, players will have to react to the ebb and flow of the game. Enemy units are offensive by nature and come in waves, usually increasing in strength the longer the game. They will fight back against the towers as they swarm past. The player will have to attempt to repair weakened towers in the heat of battle. As the level progresses, players will be given the opportunity to upgrade their towers, buffing their attacks and defense stats, changing firing patterns, speed, and power, or even replacing towers with better options. While the opening planning section feels like a turn-based strategy game, during gameplay, tower defense games more resemble a real-time strategy game.

Between levels, they’ll have to restock their defenses. Permanent upgrades are typically applied between stages, enabling you to have upgrades in place before another round begins.

Problem-solving is fun, and tower defense games are a mix of strategy to be perfected and puzzles to be solved. A TD player has everything they need for success, but it’s up to the player to work out how to create the winning strategy. Because of the variety of systems interacting in a game, from the route the creeps take to the placement of the towers, crafting a winning strategy can feel like a powerful personal achievement. Given how much of the game is won before a tower fires a shot, or a creep takes its first step on a map, it strongly rewards a perfect plan.

Being rewarded with progressively better units and upgrades will add to that feeling of power and progress.

It’s also incredibly satisfying to watch your defenses battering away at incoming enemies. The visual element, where increasingly busy battles fill the screen, is a reward in itself. They’re fun to play, but fun to watch, too.

A good tower defense game will have a number of elements that make the player feel powerful and engaged.

During the set-up, the player should be able to craft a defensive strategy that is personal and unique. They’re striving to solve a complex puzzle that has several variables, and a good tower defense will present a balanced number of options for the player to experiment with. They should feel capable but not overpowered nor overwhelmed.

Because there’s a passive element during the real-time phase, ensuring the players are engaged during the assault stage of the game is crucial. Abilities that let the player fix any holes in their defenses, repair towers, and meaningful and fun upgrades will provide a platform for player expression and progression.

They should also include a variety of enemies to engage in battle with. Multiple units, with different buffs and attacks, will give the player a lot to consider. As long as they aren’t overpowered, it should be great fun working out the best method to counter their approach.

Online play is available in a number of tower defense games.

Co-op play is available in a number of tower defense games.