This is a real time strategy game where two fortresses square off against each other. You build each fortress by dropping rooms in from above. The little men inside will move between rooms to activate defenses and special abilities, while also running between the fortresses attacking each other.
Building a fortress is similar to playing Tetris. You have a four block wide area that you can drop rooms in from above. Unlike Tetris, these only come in basic rectangle shapes. Also, the pieces are not random. Or not completely random. Think of it like a card game. You might have five rooms you could potentially drop, from which you select one - after which you draw a new random room to take it's place.
Rooms will automatically connect to each other. If two rooms are side by side and the floors match up, a door will be created. For rooms that are only one square high, a latter will automatically be placed going up to the next room (assuming the square does not contain something blocking it). Stairs are not created automatically and are part of the room you drop. Be sure to drop the rooms in a place where it won't connect to another room.
Rooms can take damage from enemy fire or sabotage. When they take too much damage, they explode damaging neighboring rooms. Then, in the hole they leave, the rooms above it will drop down into its place (if possible) and relink the doors and ladders accordingly. The drop down will incur even more damage, potentially creating a chain reaction of exploding rooms.
In the traditional of my composition grid ideas, each room has special abilities which can affect the rooms it is near, touching, or on top of. For instance, some rooms have a drop ability that goes into affect the second it is dropped (spawn two units, enemy moral down 5%, etc).
A room may also have an idle ability that happens as long as the room is in play. Resource rooms may increase the production of resources. A barracks may spawn a new unit every thirty seconds. A power supply room may be required next to a computer room to keep it going. Stuff like that.
Rooms also have manned abilities. These require units to be present in the room working the ability. The simplest one is a simple cannon which fires out across the way to the enemy fortress. As long as there is a unit in the firing seat, it will operate. Some rooms may increase capability with additional units. For instance, a power supply room may generate 1 watt per second, but with two units manning the stations, it generates 2 watts.
Some rooms generate vehicles like helicopters and what not that require a pilot. When the vehicle is destroyed, after a countdown, it will respawn in the hanger room.
You can build attachments on the outer walls and roof of your fortress. You can build stuff like auto turrets, radar dishes, manned cannons, shield walls, extendable bridges, and even zip lines. These are generally pretty weak and go down quickly, but they can make a difference. If you drop a room on top of them or something, they will be destroyed instantly. Also, you cannot build an attachment on a wall that has an open side, like a hangar or turret room.
Units can be assigned to a specific job, like engineer, soldier, scientist, spy, etc. Doing this will basically set their strategy for the game. While an carpenter may wander around the fortress repairing damaged rooms, the engineer may seek out special rooms requiring his expertise. The soldier will start by outfitting himself from the specific rooms, then heading over the enemy fortress, either by foot or vehicle or whatever.
The goal of the game is not to destroy the enemy fortress, but to kill the king inside it. The king is like a super unit, capable of working as any type of unit at double capacity. That is, a king in a power supply room will generate the additional power that two engineers would. A king is also worth two soldiers. So the king is really powerful, but of course, using him puts him into significant danger.