If it's crap ... We'll tell you
The tower defense genre is can be explained as simply as the player fighting against waves and waves of enemies, defending a certain point on the map, and earning money to create defenses to survive. This game is a great example of that, but not perfect.
You play as "The Apprentice". The last of the War Mages and the only one who can save the peaceful lands from the rampaging Orc army. Portals located inside your fortress's will lead the Orcs to your villages, and its your job to kill each and every one before they do. With your armory of weapons, traps, and gaurdians, you will have plenty of ways succeed.
The game is a played from a third person perspective, very unusual for a tower defense game. Your character must use the money you earn from killing Orcs to build defenses, while he himself is active on the field. You earn new traps and spells by completing levels, as well as earn skulls you can use to upgrade trap to be more efficient. Between each wave, you are given time to run around the fortress, get an idea of where you can place your traps, and what places would be most effective to kill them.
I started feeling like this guy was the one who designed the Temple of Doom. You get a wide range of traps, from Arrow walls and saw blades, spiked floors and tar pits, to explosive barrels and acid pools. The problem i had with the game is that you don't get them all at the start. The early levels the game are fairly simple, but it gets so difficult so quick, that you either choose an easier difficulty, or complete earlier levels to earn more skulls to upgrade your traps. I found myself stuck on a few levels to the point where changed it to easy just to pass it and earn a new trap that i could use to go back and beat it normally.
Not to say that I didn't have fun. Sending Orcs flying with catapult floor traps into lava and acid pits, freezing a group then shattering them all with one swipe of my sword, or simply letting them walk into my "HALL OF ARROWS AND SPIKES". There are a wide range of Orc to kill, simple cannon fodder soldiers, long range crossbow fighters, Giant Elemental Ogre's, and flying fire breathing dragons. No one trap can defeat everything, so you have to be creative when you choose what traps you want to choose.
The game is very easy to learn, but in order to progress further, you might need to replay it several times. This might turn some people away, and rightfully so. Be patient, the game rewards you with new ways to slaughter and slice and burn and freeze and skewer and crush and....well you get the idea.
(Since you cant "Rent" a downloadable game)