Sanctum 2: The Pursuit - PC [Steam Online Game Code]

Pursue the Titan through the outskirts of Elysion One! This expansion adds even more replayability through four completely new maps! Use two new towers, including the Mind-Control Spire that takes control of enemies and lets them fight for you! Unlock new devastating weapons, such as the Drone Launcher, that launches target-seeking drones that home in on enemies and shoot lazors at them. They'll be all like "NOO NOT THE BEEES!"

Of course, there are going to be new enemies as well, such as the Heavy Pup that's far more aggressive than it's older equivalent, and the flying Bliskeblaske, which you'll just have to see for yourself.

Finally, you'll be getting seven new unlockable perks as well - for example, the Reinforcements perk has a chance to spawn Explorers with shields every time you kill an enemy!