PolyGun: Idle TD is a free online idle tower defense shooter where you control a powerful auto-firing turret and hold the line against relentless waves of geometric enemies. Every polygon that charges your position moves differently, forcing you to think strategically about upgrades rather than just watching numbers climb. The idle mechanics mean your turret keeps firing even when you step away, but active players who invest in the right upgrades will survive far longer.

The card-based upgrade system is where PolyGun really gets interesting. Unlocking and stacking cards lets you build custom power combinations, turning your turret into something genuinely destructive. Daily rewards and quests keep giving you reasons to log back in, and the challenge system adds short-term goals that make progression feel rewarding rather than grindy. Geometric enemy patterns scale up fast, so learning which upgrades counter which movement types becomes a real skill.

If you enjoy idle games with active depth, or tower defense games that reward smart decision-making over mindless clicking, PolyGun hits a strong middle ground. It works perfectly as a browser game you check between tasks or a session you sink real time into. Fans searching for free idle shooter games, polygon tower defense browser games, or no-download survival arena games will find exactly what they are looking for here. No install, no cost, just pure auto-shooter strategy from the first wave.