One of my earliest favorite games was nothing more than firing cannonballs at an enemy's tower, adjusting angle and gunpowder to achieve the proper impact. Simplicity doesn't mean simplistic, you know? The essence of fun goes way beyond judging books by their covers, as so many good-looking but low-quality games demonstrate. The interesting thing about Defense Grid: The Awakening is that it doesn't actually sacrifice anything in the way of good looks. Although 80% of the game is static, you start looking at the details and realize that everything is crisp and designed incredibly well. The towers you'll use as your tools during the game have great attack animations, and the enemies moving throughout each level are eye-candy enough, but the real brilliance of Defense Grid is in the level design. It's called tower defense, but there's a strong puzzle aesthetic at work here.

If level design is the leading man, your incorporeal narrator in Defense Grid is Best Supporting Actor. The craft of writing his parts is improved on by some great voice acting, including moments that bring a genuine smile to your face. Nothing about this game should naturally elicit such a response, which just goes to show that the creative minds behind Defense Grid were inspired to make something exceptional. Saying the action heats up during a level is somewhat of a misnomer, since those towers you are using to defend don't move an inch, but the sounds of battle definitely ratchet up as you progress. There are a number of visual and sound cues that tip you off to things happening while you play, letting you know when it's time to change focus. The camera controls are keyed to the left and right stick on the controller, left to move the camera and right to select the viewing height from one of three levels. It's all very smart and intuitively designed.

Tower defense is not that different than the gameplay behind many real-time strategy franchises, and fans of any of the long list of RTS titles will instantly "get it" after booting up their first round of Defense Grid: The Awakening. The key difference between a pure tower defense strategy game and the conventional RTS genre is that TD greatly simplifies the concept of gathering and using resources. Defense Grid keeps things particularly simple: Your towers can't be destroyed, and the resources needed to build them are almost exclusively reprocessed from destroyed enemies. This type of build-destroy-build concept removes all the nuance of having to manage your own attacking and defending force, while simultaneously gathering resources and building units. The nuance here is instead wrapped up in your choice of weapon and your placement of towers while the enemy horde masses against you.

PC gamers have had Defense Grid: The Awakening for a while now, so you may have already heard the basics from some ardent fan. The basic campaign hasn't changed in the transition to XBLA. For newcomers, the exclusive goal of your enemies is to grab power cores you desperately need to survive each level. You'll see at least one entrance and exit marked clearly as you launch a new level, with later areas also showing travel paths for flying enemies. The cores are stored together, so you have to protect them by orienting your towers to ensure that enemies don't reach the cores or don't escape the level with any cores they grab. Some key differences between the Xbox 360 and PC version are that there's more content on the Xbox 360 port, with a "Borderlands" expansion bundled in the version of the game you'll access for a paltry ten clams from XBLA. You'll also find challenge levels attached to each of the standard missions that force you to rethink the strategy that worked well during your first round. In one, you'll be forced to use nothing but "green" or basic towers to win, while another turns the concept of saving cores on its head as you try to prevent a "poison core" from killing your score.

Analyzing levels is a major differentiating factor between the early and later stages of gameplay. Sure, you get more powerful weapons as the game progresses, but this just increases the chance of analysis-paralysis. A really important element of Defense Grid mentioned earlier is the puzzle aspect, figuring out which combination of towers will achieve optimal results. Placing a low or moderately powered weapon in every available space may work at first, but isn't a good long-term strategy. Smarter players will recognize the value in upgrading weapons, and holding onto resources to build capacity more quickly on a just-in-time basis. None of the levels are incredibly long, especially when you can tap (RB) to speed things up, so the learning curve is not terribly frustrating. Solutions to each level are quickly discovered through experience, by watching where enemies creep through your defensive lines and reacting the next time you attempt that level. Earning all the achievements and mastering extra levels will take considerable skill and patience, making Defense Grid a game that can be enjoyed in part at a casual level, but which will require some experience or commitment to complete. If you've never felt the thrill of victory in a traditional RTS, there's a chance that you may do better with Defense Grid, but only a slim chance...

Fighting as one against many is instantly a cool feeling, and the weaponry at your disposal is awesome to behold. Watching the devastation is half the fun in Defense Grid, but you'll have to keep your eye on several other things to really master the challenge. Each tower type features a weapon that is generally well suited against a specific enemy. The Gun tower is perfect for any occasion, does damage to all enemy types, and is easy on the resource pocketbook. Eventually you'll graduate to more specialized weapons, as the enemy floods in with new, and more exotic challenges. Flamethrower-style towers, the Inferno, and ranged weapons like the Cannon or Meteor function well against clustered enemies. Inferno works great in confined spaces, while the ranged weapons are only good at a distance. Temporal towers do nothing but slow enemies down, which can be used in combination with natural bottlenecks and other towers to create highly effective killing areas. The geography and placement of towers is at least as important as learning the various types. Each tower has its pros and cons, but if you fail to correctly read the level, no amount of tower placement will help you.

Controls are simple, with (A) or (B) doing their typical job of selecting or canceling, and the (Y) button displays important range information. Knowing range is key, since you can't exactly do damage to enemies you can't reach... Squeezing the trigger initiates the ultimate weapon in this game, a satellite laser that does extremely high area damage to one location on the map. Pulling off a successful attack with this baby is tricky, but well worth the effort! Controlling Defense Grid is a dream, and even PC gamers will quickly forget they are holding the Xbox 360 controller instead of driving a mouse and keyboard.

Defense Grid is completely addictive, righteously aggravating, and impossible to dislike. Part casual game, part puzzle game, and always strategic, it is the thinking man's alternative to run-and-gun action or cutesy RPG fare. There's nothing quite like it on XBLA, and precious few ways in the world to get more entertainment for $10 that won't make you fat.