Wow, well this is certainly no hit, but is really not that bad...
You start out building your pixelated fortress out of falling bricks and try to make the most easily adaptable structure. The bricks fall down Tetris-style and are accompanied with cannons, little doorways for your workers, and your main gate, which you set down as the first piece in the beginning of a match. The objective is to be constantly rebuilding, repairing, and expanding your fortress faster than the opposing computer player can with its. The only other thing you can really control is the place to which your cannons will fire.
Starting out, this game is confusing. Later, it is still a bit confusing. The most interesting thing about this game is that if you set your blocks in the right combinations, then you can create different "towers." These towers allow you to summon up monsters that will reduce the opposing fortress to practically dust. The only problem is that you have to figure out how to make these towers and that the computer knows how to make these towers as well, but faster.
Fortress' graphics are not stunning. More like ugly, but the graphics are not really that important. The game is good to waste time with, but hard to get the handle of.