Genre: Action/Strategy
Publisher: Microsoft Game Studios
Developer: Hidden Path Entertainment
Release Date: November 2008

My experience with tower defense games is limited to a few online Flash games. The gist is to protect your base/tower/castle from hordes of enemies that would attack in multiple waves. Hidden Path Entertainment has taken the addictive quality of these games to create a polished version of their own with Defense Grid: The Awakening.

Defense Grid takes place in a postapocalyptic Earth, and many of the planet's inhabitants have perished. The few who remain survive on limited energy sources, which are also coveted by a group of alien invaders, so it's up to the survivors to build towers to protect the energy sources. The goal is to prevent your foes from taking the energy sources, which are in the form of small glowing orbs. If an enemy manages to make it to your base and grab some energy, you can still destroy him, and your orb will slowly travel back to its original location, although other enemies can still pick them up. This objective allows players of all skills to be able to play Defense Grid. Novice players can still win by having as little as one energy source remaining, whereas skilled players will be rewarded with bonuses for not allowing any of their resources to fall into enemy hands.

The main game will feature 20 stages of varying difficulty, although the demo only showcased two of the levels. The first stage was fairly early in the game, and the map was pretty easy. Essentially, it was large, square horseshoe with a sizeable platform in the middle. My energy sources were on one side, and the enemies approached from the opposite side.

On the middle platform was where I could build towers to fend off my foes. Towers come in a variety of forms, including: cannons, flamethrowers, lasers, teslas and turrets. All of these weapons have varying power and effectiveness against certain enemies. For example, there will be shielded enemies that will reflect lasers and flames, but once a turret destroys the shield, all of your artillery will smite them.

There are also some annoying enemies you'll encounter, such as ones that'll fly across the map and others that will navigate to the middle of your map and create portals to summon more invaders to storm your base. Defeating enemies will allow you to harvest resources that can be used to build more towers or upgrade them. Towers can be upgraded twice, and you can discern a tower's level from its customizable target radius of green, yellow or red, with green being the weakest and red being the strongest. This color code is also used on a gauge that shows you the types of attacking enemies.

The other map I played was much more complex, and it consisted of several bridging platforms, which displayed the true beauty of a strategy game. Enemies will take the shortest and easiest possible route, but they'll also take the long route if it means reducing the barrage of turret fire that hits them. You create a maze-like structure for your enemies with the towers you build, and these mazes need to let your enemies pass; you can't block off all pathways, or else the invaders will force their way through your defenses and foil your scheme. With careful planning and well-placed towers, protecting your resources should become second nature.

A couple of things that impressed me with Defense Grid, aside from the addictive qualities, was how detailed the environments were, and the lack of slowdown when several dozen units were on the field at once. You can get a more detailed view of the action when zoomed in, or get an overview of the area from a bird's-eye view; the strategist within me preferred the latter. The build I was playing wasn't quite complete with the visuals, so it was a little difficult to differentiate the background debris from the actual playing field, but even at this point, the title looks great.

In games like these, the sound doesn't matter all that much. The missions that I played featured a few voiceovers that would direct me to my objective (protect the energy) and notify me when a new wave of enemies was going to approach. Other sound effects, such as explosions and gunfire, were pretty good, but overall, it's not something I'll take into account. In my opinion, this genre is best complemented with listening to your own music on your computer.

I'm looking forward to checking out the final version of Defense Grid: The Awakening when it's released as a download title for PC and Xbox Live Arcade. Fans of tower defense and real-time strategy games should also keep an eye on this title as it approaches its launch date.