Warkeep is a healthy mix of tile-matching puzzle elements to build a defensible keep, and a side scrolling tower defense game to see it destroyed (we're kidding, hopefully you can defeat the enemies and its not destroyed). You use tile-matching in order to build up the keep by combining random block pieces, rooms, and towers to enclose the Keep Core (shown as doors ingame). From there, waves of enemies with one focus in mind (a pile of rubble) stream from both sides of the screen. Rooms will spawn friendly units which will passively engage these enemies, while the towers will rain terror down on the enemy.
Warkeep can be played multiple ways. At its core is the tower defense elements where your focus is to keep the enemies away from damaging the keep core (the lose condition). As enemies are killed, you will gain gold which can be spent to upgrade the overall keep (provides better defenses), the rooms (better defenses and unit), and the towers (better unit). You also have your trusty hero which can be sent out to fight for you with controls reminiscent of an RTS game, and a handful of activity abilities if you want to get your hands dirty.