If you've never played a tower-defense style game before, the premise is pretty simple--prevent your enemy from moving from point A to point B by setting up your defense ahead of time. In a small twist to the usual tower-defense genre, LOTR: Middle-Earth Defense features "defense structures," as well as heroes/soldiers. Defense structures block the enemies' path and force them to go a different way--and this is imperative to winning the game.

You have three different types of defense at your disposal: regular defenders (lesser characters, such as the hobbits and Boromir, as well as nameless soldiers), heroes, and defense structures. The regular defenders are cheaper and less powerful than the heroes. The heroes--Aragorn, Legolas, Gimli, etc.--are more expensive, but have special magic abilities (e.g. Gimli has a whirling axe move) that can be called upon occasionally in order to get past the harder levels. Defenders (mercenaries and heroes) can be placed in certain areas around the map, as indicated by blue spots. Defenders can also be upgraded in an RPG style (attack, speed, range, and skill can each be individually upgraded in all heroes, while attack, speed, and range can be upgraded in regular defenders).

The other type of defense is "defense structures," which is exactly what it sounds like...structures for the purpose of defense. Structures can be as simple as wooden spikes (which do no damage, but change the enemies' path) to objects that slow down and/or do damage to the enemy. Structures require wood, not coins, to build, and can be placed on any of the orange spots on the map. In many cases structures are an absolute necessity--for example, if defenders can only be placed in certain areas away from the flow of the enemy, a structure is necessary to direct the path of the enemy toward those areas.

There are two different modes--story mode and challenge mode. In story mode, you will play through 18 different levels set across seven famous LOTR backdrops (including Minas Tirith and the Mines of Moria). You'll also be able to unlock characters in the story mode that you'll then be able to use in the challenge mode--which is basically wave after wave after wave of enemy, just seeing how long you can survive.

There are very few drawbacks to LOTR: Middle-Earth Defense, especially if you're a tower-defense and/or LOTR fan. Some of the missions can last up to 20 minutes, which means you'll definitely get a solid four or five hours of play time. The visuals are also gorgeous--especially the map of Middle-Earth--and iPhone 4 users with retina screens will especially be impressed.