Tower defense titles thrive on repeatable tension. Short wave timers paired with generous upgrade panels keep players in a loop of assess, deploy, reward.
Developers are leaning on seasonal metas to reset the experience. Limited-time relics or boss modifiers give veterans a reason to rebuild their loadouts from the ground up.
Monetisation stays subtle: cosmetic map skins and optional fast-forward tokens support creators without locking progression. That balance keeps daily retention high.