Saturday, February 28, 2009

defense grid: the awakening

Ages ago, I blogged about the sublime and somewhat embarrassing joy of tower defense games. They are designed for casual distraction - quick, easy to pick-up & play, and cheap. There are dozens of free tower defense games you can find on the interweb, but I'll admit I haven't played any of them extensively except for that timeless classic, Desktop Tower Defense.

Tower defense games are all based on the same principles. You have a map with an entry point and an exit. Enemies, or "creeps," appear at the entry and make their way unintelligently (using simple deterministic rules) towards the exit point. As player, your job is to build defense towers that will destroy the creeps as they pass by. The more creeps that escape, the more "life" you lose, until the game ends. The strategy of tower defense comes in 1) placement of towers and 2) types of towers. You can place towers in such a way as to create a maze for the creeps, thus making their journey longer and giving you more opportunity to destroy them:

In addition, there are different tower types to build. Some may have a high rate-of-fire but only target one creep at a time, whereas others can damage large clusters of creeps but only occasionally. You get the idea.

Tower defense games are an amusing distraction but as a general rule, I typically require more meat in my gaming diet. Plus I'll admit to being somewhat of a graphics whore - I mean, I invested in this fucking Windoze PC and whammy-dine graphic card, I want to see some benefits.

Enter Defense Grid: the Awakening.

If we ignore the absurd colon-ized title, Defense Grid is the best thing to happen to tower defense games since... well, Desktop Tower Defense. Furthermore, I'd argue it's the penultimate tower defense experience. It's got 20 different maps to play on, each presenting different strategic challenges. It's got 15 different creeps to deal with, ranging from the simple test-drone...

... to devastating Juggernaut...

It's got 10 different tower types to play with and each can be upgraded twice:

  • Gun: Versatile machine gun turret. Especially effective against shielded and flying enemies.
  • Cannon: Long-range projectile weapon. Low rate of fire but heavy damage. Effective against strong and shielded enemies.
  • Inferno: Flamethrower-based tower, with continuous rate-of-fire. Effective against large groups.
  • Laser: Laser that inflicts damage over time. Effective against fast enemies and certain bosses.
  • Tesla: Fires lightning bolts. Deals more damage the longer it is charged. Effective as a last line of defense at exits.
  • Missile: Anti-air missile tower.
  • Command: A tower that increases revenue per enemy killed and reveals stealth units within its radius.
  • Temporal: A tower that emits energy pulses and dramatically slows enemies within its radius.
  • Concussion: An area of effect weapon that fires explosive grenades. Effective against large groups.
  • Meteor: A long-range tower that launches a superheated fireball at the enemy. Effective against large groups. 3rd-level upgrades of this baby are a thing to behold.

And it's got pizazz:


Defense Grid is a thoroughly visceral experience. The creeps come in waves and you'll typically need to defeat ~15 or so to progress to the next map. By the time you get to wave 15, you'll be in tower defense heaven: juggling tower builds & upgrades, shoring up weak spots in your defense, suddenly realizing you have nothing to defend against fliers, and basking in the multicolored glory of your impenetrable defense network.

The creeps in Defense Grid have a goal. They want your power cores. So their first stop on the map will be the power core station, they'll pick up as many as they can carry, and then they'll head for the exit. In order to build towers to prevent them from escaping, you'll need resources. You typically start each map with enough resources to build half-a-dozen simple towers, and you acquire more resources every time you destroy a creep. The fundamental challenge of the game is to make sure you keep building and upgrading towers as you collect resources to match the increasing difficulty of the waves. Pause too long to enjoy the scenery and things can get ugly fast.

Since screenshots don't really give you a feel for what this game is like, here's a brief trailer:

Defense Grid does so many things right, I have to give props to the designers. The maps are aesthetically pleasing and varied enough that you're always looking forward to what's next. Some maps tightly restrict your tower placement points, which challenges you to make every decision count. Some maps give you enormous freedom of where you can build towers and in these, the goal is always to create some sort of twisting maze-o'-doom for the creeps. For example, here's the map "Waste Disposal" - one of the most difficult in the game:

The creeps will take the shortest path to the power cores, so you need to cut off their movement with towers. But maps like Waste Disposal give the creeps more than one path to take, so the pressure will mount as they sneak by your defenses. You also have to worry about line-of-sight (towers placed in front of other towers will reduce their effectiveness), timing of upgrades (while upgrading, a tower doesn't fire), and creep decoys who draw your tower-fire while their more armored comrades rumble past and steal your cores. For such deterministic little bastards, the behavior of an entire wave can begin to appear strategic.

For the obsessive out there (and that's pretty much anyone who likes tower defense games), each map also comes with a number of "challenge modes." For example, you can try to earn silver and gold medals on each map by getting higher scores and ensuring that none of your power cores leaves the map. Some challenge modes limit you to only 10 towers total - some give you a set amount of resources at the beginning but that's it. I can't emphasize how much more depth and gameplay these modes give Defense Grid. It is thoroughly addictive trying to achieve a Gold Medal on every map at the hardest difficulty level. Fortunately, the designers included both a speed-up function and autosaved check-points which facilitate rapid trial-and-error in the pursuit of perfection.

I've poured dozens of hours into this game and enjoyed it much more than I thought I would. For a measly $20 on Steam, it's a bargain waiting to suck every last free moment of your time. Indulge.

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