Edgeworld

Edgeworld is a free-to-play browser-based social game launched in 2011. The game is a strategy tower defense/offense game. On defense, players build a base and set up defensive towers. On offense, players train up their units and launch them against enemy bases. The game offers a variety of units, technology, and upgrades, and monetization is accomplished via premium currency used to instantly upgrade buildings or purchase items to unlock unique units.