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.

Tuesday, February 24, 2009

don't divorce us

I'm really excited about getting married. For so many reasons.

With that in mind, please take the time to watch this very lovely little movie:

"Fidelity": Don't Divorce... from Courage Campaign on Vimeo.

Thursday, February 19, 2009

time travel as plot device

If you're a fan of science-fiction, at some point you have to confront your own personal feelings about the use of time travel in narrative. My father, for instance, absolutely detests time travel. It nearly always creates a series of paradoxes which, for him, destroy the suspension of disbelief necessary to enjoy the story. And certainly, there are numerous examples of movies and books that prominently feature time travel as a plot device to their own detriment. I'd have to put the whole Terminator series in this category. Given how easy it has become in the future to create and send back homicidal robots, I just don't see how/why anything in these movies actually matters.

Then there are stories that feature time travel but the plot is kept constrained so that we don't care about potential paradoxes. In particular, these stories avoid discussion of the so-called Butterfly Effect (as it applies to time travel) wherein a minor alteration to past events can lead to an entirely new future. This idea was first penned in a sci-fi context by Ray Bradbury, in his short story "A Sound of Thunder" (parodied amusingly in the Simpsons episode, Treehouse of Horror V).

For example, consider Planet of the Apes, Bill & Ted's Excellent Adventure, and 12 Monkeys. Time travel exists but we need'nt worry about our protagonists fucking things up.

Then there are movies that focus quite specifically on this paradox, but do it with so much style and thought, we are moved to forgive them. The excellent and perplexing Donnie Darko is a good example of this.

We might very well place the indie movie, Primer (2004), in this category as well. I watched it a fortnight ago, with my DVD remote close at hand, and indulged in its time looping depravity. Briefly, the film takes a very modern, engineering approach to time travel. What if two young technical entrepreneurs successfully created a time travel device? One that could only take you back in time, mind you, but worked nevertheless. And what if they not only used this time machine to make money (in the predictable stock market way) but also to affect their personal lives and relationships?

I'm not sure how much more I want to tell you about it, except that it's probably worth seeing. Many, I'm sure, detested it. My god, this movie is probably the worst possible thing I could have my father watch. But I appreciated how seriously the writers took the topic of time travel - the paradoxes form the basis of the entire narrative structure.

The only way to resolve time travel paradoxes (and it's not entirely satisfying, of course) is to create alternative time-lines (universes) every time someone activates a machine. This is necessary because the mere presence of an individual in the past creates a different future. Furthermore, it prevents infinite loops that would halt all of reality (travel back to the past, live, eventually travel back to the past, live, etc. - the so-called, predestination paradox).

Here's a simple schematic of the time travel in Primer, which could very well apply to every story featuring temporal movement.

But that doesn't cover the details at all. Just for kicks, take a look at this:

It's the complete breakdown, created by some committed fan of the work. After watching the movie, you might want to at least glance at it to see if some of your suspicions are confirmed. Regardless, my tiny human brain could not process all of these possibilities at once - and so, ultimately, Primer must be judged on whether it is a satisfying artistic experience. I'm not sure if it is. It really is all about the time travel - there's nothing else that matters - and if that frustrates the hell out of you, the film-makers say, "too bad, you probably shouldn't have rented this."

If you want something quite different and ultimately more satisfying, I might suggest another book by my favorite author, Gene Wolfe. Pirate Freedom looks cheesy as hell, but like everything Wolfe, it's deeper and more challenging than you initially expect. Overtly, it's a tale of a boy who somehow (never explained fully) travels back in time to the golden age of piracy in the 17th century. The narrative is revealed as a first-person account, typical of Wolfe, in which you as the reader must constantly wonder at how much information the narrator is failing to reveal or simply lying about.

Fortunately, you can enjoy the book as historical fiction about what it may have been like to be a pirate in those days. Wolfe is obsessive about his research, and if you know anything about the history of piracy, you'll be able to identify important events and patterns in the text. For example, at one point early in the story, our protagonist, Chris, is left on the island of Hispaniola by the English privateer, Capt. Burt. On Hispaniola, Chris falls in with Frenchmen surviving by hunting wild cattle - the historical origins of the buccaneer. It's an action-oriented plot, and it's about pirates god damn it, so there's killing and torture and raids and booty and even hidden treasure. Wolfe never forgets the essential trappings of whatever genre he is writing within.

But of course, there's a time travel element involved, and only towards the end of the book do we get a sense of its implications. Depending on how you feel about Wolfe's writing in general, you may find this intriguing or incredibly frustrating.

I'm curious to know how other people feel about time travel as a narrative device. Leave a comment if you're so inclined.

Friday, February 13, 2009


It remains to be seen whether Twitter is simply another passing tech-fad, the ultimate voyeuristic experiment, or a herald of something far more disturbing to come. Clearly, it's the height of obsessive narcissism and a cry out for social comfort in the deafening loneliness of our time - oh wait, that's blogging. Regardless, I'm not one to care much about people's micro-updates ("I'm taking a crap!" "I'm eating a burrito!" "I'm having sex with your girlfriend!") on an individual level, but once you start letting me compile data from thousands of cyberhipsters (did I just coin that term?) I might start thinking Twitter is a scientific tool.

Twist (or Twitter Trends) allows you to see the % of twitters that mention particular words over the course of a week or month. So, for example, if you type in "Darwin," you'll see a peak (nearly 1% of twitters) yesterday around 10:00am. Boring.

I'm more curious about cursing frequency. So, for kicks, I put in "fuck," "shit," and "cat" (my control group). These are the data:

(click for larger image)

So there's clearly a circadian pattern in use of both fuck and shit. The vertical gray lines represent midnight, so the daily peaks for these two words occur around midnight or soon thereafter (I am assuming that these times are "local" to the person tweeting). Also, the weekly peak for "fuck" and "shit" occurs right around midnight between Sunday and Monday. Why don't I find that surprising.

Twist also lets you see some of the Tweets it's sampling. Here are some examples from my experiment for you to ponder and contemplate:

"my roommates show up with groceries and start cooking lunch as soon as i start recording. fuck the kitchen. i wish i still lived alone"

"So angry, gonna punch a cat inna mouf. Fuck yeah."
(this one contributed to 2 of my trends - amazing!)

"When one of these rap niggas finally kills another rap nigga, I'm going to be RIGHT THERE to say, 'I AINT SEE SHIT.'" (Damn!)

"When you install an Adobe product, they really put so much shit on your computer you don't want."

True that.

Wednesday, February 11, 2009