Tower Defense Games
Tower defense games ask you to protect something by planning, not by fighting directly. Enemies arrive in waves along a path, and you decide where defenders go and when to upgrade them. The tension comes from watching your setup meet the next wave and seeing where it holds.
Related topics
What counts as a tower defense game here
A game is listed when you place or upgrade defenders to stop waves of enemies, or when the whole game is about defending a base, castle or fortress. Defend the Castle has you spend gold and wood on defenses, Empire Tower Defense - Zombie Fortress asks you to position archers against the undead, and Siege Break has you drag heroes into slots around a besieged base. Avenger Guard and Plant Merge: Zombie War add merging, and Pinball vs Zombie uses plants and a bouncing ball.
How to pick one
Decide how much planning you want. Classic defense games with resources reward slow, careful placement, so they suit longer sessions. Versions that add merging or pinball change how you place and upgrade defenders. Early on, spend on defenders that cover a long stretch of the path, then upgrade once you see which wave breaks through. If one setup keeps failing, rearrange it instead of adding more of the same.