Building a Better Alien Trap - 8.0 Great Game12/22/2008 by Jason Ocampo | Source: IGN
Tower defense games are a dime a dozen on the Internet, which is a bit of an exaggeration only in the sense that the vast majority of them are free-to-play, so paying 10 cents would be overkill. Still, it's not surprising that tower defense games are so popular; done correctly they can be an addictive time suck, draining away the hours as you attempt to establish a defensive system that can withstand everything the computer throws at it. With all of these free games out there, is there room for a premium tower defense game?makes a compelling case with , a $20 game that offers plenty of tense moments and much more depth than a typical tower defense game.
Defense Grid is set in a distant future where you must protect the last remnants of a mighty civilization from an alien menace. To make a long story short, it all comes down to keeping power cores out of the aliens' hands. On each level, the aliens enter the map and travel the shortest path to the power cores, and then they make the way to the exit. If they escape with a core, that core is lost. If the aliens escape with all the cores, you lose and must try again.
There's nothing more satisfying than a stout defense. To prevent this, you must build and upgrade defensive towers that pound the aliens with different weapons. There are gun, laser, and cannon towers; concussion towers that rain cluster munitions; missile towers for aerial units; meteor towers that serve like artillery; inferno towers that are basically flamethrowers; Tesla towers that electrocute the aliens, and a temporal tower that slows them down. However, the more powerful towers cost a lot in terms of resources, and upgrading them is even more expensive. Since the only way to "earn" resources is to kill aliens, each level is a desperate race to design and implement an optimum defensive grid.
To make things more difficult, the aliens come in many different varieties. There are juggernauts and shielded juggernauts; these are basically huge, lumbering behemoths that are extremely difficult to kill. Then there are decoys, which are basically whipping boys that are designed to absorb an insane amount of damage so that the aliens following it remain relatively unscathed. There's an alien boss that shields any other aliens that make contact with him. There are speedy aliens that can race through your defenses, making it difficult to inflict a lot of damage on them. There are flying aliens that can bypass all your ground defenses. There are horde aliens that come in huge packs that can overwhelm defenses designed to target single aliens. There are turtle aliens that, upon death, unleash a horde of units.
Each level will throw anywhere between three or thirty waves at you, and each successive wave is designed to push you to the limit. Thankfully, a warning system lets you know the composition of each wave in advance, so you can try to prepare for it as best as you can. If you see a wave of racers coming in, you know you need to build and upgrade laser towers, as they do the most damage against them. The balancing is very well done. It's very difficult to stop some of the more advanced waves without losing some cores. The good news is that there's a very handy checkpoint system that lets you instantly revert to a previous checkpoint by just taping the backspace key. And the game does give you a powerful superlaser, though you must be very strategic about its use, as its recharge time is considerable.
Place down towers to shape the battlefield.Defense Grid has 20 levels that ramp up in difficulty as you go. At first, the aliens will travel a long, narrow, linear track that's easy to defend, as there are plenty of places where you can build towers. However, the levels get more difficult, as there may be separate tracks or multiple entrances to worry about. The best levels are the more open ones; there isn't really a track, but rather a relatively empty grid that you have to "mold" by placing towers down. These are extra challenging because you have to try to build a maze while you're busy fending off the aliens. Level progression is challenging, but the last level the difficulty curve takes off like a NASA rocket; it's frustrating, but ultimately extremely rewarding to beat. (I made it through with just a single core remaining, and that core came very close to escaping.)The open levels also provide an unlimited number of configurations, providing plenty of replayability. To further boost replayability, there are also leaderboards where you can compare your scores with others, as well as a challenge mode that amps up the difficulty.
The 3D graphics engine isn't particularly cutting-edge but it still remains far above the norms of the genre. After all, many tower defense games are Flash-based. And the 3D engine allows for three dimensional levels that have multiple tiers to them, which adds complexity and depth. The audio is also a step above most of the genre; the sound effects are workmanlike but there's also a guide that mentors you and provides commentary. The voice actor for the guide is nicely chosen, but he does tend to ramble on about raspberries a bit too much, and some lines are repeated over and over and over again.