geoDefense (iPhone)
Developer: Critical Thought Games
Publisher: Critical Thought Games
Released: February 15, 2009
MSRP: $0.99

Like any tower defense title, your objective begins simply: to place various types of towers along a set path that enemies will progress along, in order to kill them before they reach the end of it. In geoDefense, the setting has a cool retro feel to it (graphics are vector-based), which will likely resonate with fans of Geometry Wars. You can start by choosing easy, medium, hard and hardcore levels (all are open to you as soon as you get the game), although I would advise you progress in order unless you are prety skilled at tower defense titles -- this one can get tough!

Controls for geoDefense are a cinch. To place towers, you drag from icons at the bottom of your screen, which are conveniently right below your available money. To upgrade or sell a tower, you simply tap it with your finger and choose which action you'd like to take. Placement of certain types of towers is key pretty early on -- for instance, you'll be learning to place Laser towers by the second easy level you play. As each enemy dies, it explodes in a burst of colored fireworks, making for a simple but attractive appearance on-screen as you play.

You'll quickly find that there are multiple ways to use the different towers. For instance, Vortex towers work by using the debris of destroyed baddies to your advantage. You also can't get away with pausing the game to upgrade your towers as you can in some other tower defense titles, as everything in geoDefense happens in real time. 

Another thing worth noting about geoDefense is that it is a bit more difficult than your average tower defense title. If you don't figure out exactly how to use every penny of your budget exactly right and place the towers precisely, you will likely never fight your way past medium difficulty. The game has 30 levels total, and doesn't cut corners when it comes to challenge. However, I've played tower defense titles that were downright frustrating in the later levels, and I wouldn't go as far as to compare geoDefense to those. It straddles the line between too easy and ridiculously difficult quite nicely, in fact.

Rather than feature a soundtrack, the game allows you to play songs off your phone while you play. This is a cool feature, but when I imagine this game having its own kickass soundtrack, I can't help but kind of wish that it was there rather than having to create my own playlist to match it. What I would have preferred is the option to either listen to an original soundtrack or turn it off and add my own music. The sounds can be turned on and off as well, although they suit the  look of the game nicely and I'd only turn them off if I had to.

Also, if you are frustrated by games being interrupted by phone calls or texts, you'll be pleased to know that Critical Thought made a point of addressing that issue. Pressing the Home button auto-saves your game, and the same happens if you get a phone call. While a small detail, this kind of thing can make the difference between me playing an iPhone game for twenty minutes or two hours.

I would have paid four times the price for this excellent little game, and it's taken up a lot of my on-the-go game time since I put it on the iPhone. If you're a fan of the tower defense genre or strategy games in general, this one is well worth your time, especially for the super-cheap price tag!

Score: 8 -- Great (8s are impressive efforts with a few noticeable problems holding them back. Won't astound everyone, but is worth your time and cash.)