Swarm Fortress

Gameplay:

Swarm Fortress combines horde-survival and tower defense. You control a commander who must survive waves of enemies. Besides shooting the enemies yourself, your buildings will also shoot, block or generate resources for you.

Day-Night Cycle:

The gameplay is split in two phases: the day during which no enemies appear and you can spend as much as you want placing buildings, and the night during which you cannot build and must survive the enemy waves. Between the waves you will receive rewards such as resources, building unlocks, commander upgrades and allied units.

Progression:

After the end of each night, you are offered various rewards such as free building unlocks and upgrades to your commander's combat capabilities. Use them to stay ahead of the increase number and difficulty of the enemies. It is also possible to unlock specific buildings yourself by paying resources in the tech-tree tab, granting you access to key technologies without relying entirely on luck.

Replayable:

You can play this game many times and each time you play the experience will be different--based on the random rewards you receive, you may center your strategies around different types of buildings, such as high-level turrets that deal areal damage or spawners that create allied units who fight for you.