What tower defense is
A tower defense game is a type of strategy game in which players must stop waves of enemies from reaching a goal, such as the end of a path or the player's base. Instead of controlling a character directly, you place defensive structures, usually called towers, which automatically attack enemies that come within range. If too many enemies get through, you lose. Plants vs. Zombies and the Bloons TD series are popular examples.
Placing and upgrading towers
Each tower has its own strengths, such as long range, high damage, splash damage that hits groups, or the ability to slow enemies down. Defeating enemies earns money, which you spend on new towers or upgrades for existing ones. Choosing where to place each tower matters a great deal, since positions near bends in the path or chokepoints let towers attack enemies for longer before they slip past.
Waves and rising difficulty
Enemies arrive in waves, with each wave usually tougher than the last. New enemy types appear over time, such as armored units that resist certain attacks, flying units that skip ground defenses, or fast units that rush past slower towers. This steady escalation forces players to adapt their strategy, balancing spending on immediate defense against investing in stronger towers for the harder waves ahead.
Roots in custom maps
The genre grew from fan-made maps for real-time strategy games, particularly StarCraft and Warcraft III, whose map editors let players build their own game types. Tower defense maps became hugely popular in those communities, and standalone browser and mobile games soon followed. The format's simple controls and short sessions made it a natural fit for phones, where it remains one of the most played strategy genres.
Variations on the formula
Tower defense has many variations. Some games let players shape the enemies' path by building mazes with their towers, while others fix the route in advance. Hybrid games add a controllable hero, card-collecting mechanics, or base-building elements, and some flip the idea entirely so that players control the attacking side. These twists keep the genre fresh while preserving its satisfying core of planning and watching defenses work.
The bottom line
A tower defense game is a strategy game about stopping waves of enemies by placing and upgrading towers in the right spots. Its mix of planning, resource management, and steadily rising challenge makes it easy to learn yet surprisingly deep. From its origins in custom strategy maps to its success on mobile, it remains one of gaming's most addictive and approachable genres.
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See also: What is a MOBA? Explained, PC game stores explained: Steam, Epic, and GOG.
Sources
Published date reflects the original event date (2026-10-24). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.
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