The High Water Mark for Tower Defense
In an era where the tower defense genre has become increasingly prevalent, both as simple online flash games and as actual disc and digital download products, it's becoming ever so slightly oversaturated, although not quite to the degree of third and first person shooters. All of a sudden there are dozens of tower defense games to choose from - and all have their own merits. So sometimes it just comes down to which game has the most charm, and/or which game can execute on its ideas the best. Defense Grid: The Awakening, a Sci-Fi tower defense developed for XBLA and PC by Hidden Path Entertainment, is perhaps the finest example of the genre since PixelJunk Monsters for PSN. The game has some charm to it, but in truth this game is all about the supremely intelligent design; Defense Grid is simple one of the most polished games you can find on Xbox Live Arcade.
While many amateur game designers have cut their teeth on tower defense, Defense Grid: The Awakening actually has some significant development experience behind it, as the game credits include Mark Terrano, one of the masterminds behind the highly acclaimed PC RTS Age of Empires II. That experience in design and care in craft is evident from the sleek visuals, simple yet effective sci-fi art style, and of course the game and level design. It also helps that there is an incredible variety to Defense Grid; there are 20 maps in the core game but while there are the basic story missions, there are also different type of game modes with different win conditions, which I will elaborate on later, but first, let's get back to basics.
The thing is, tower defense might be descended from real time strategy games, which is one of the most complex, deep and at times impenetrable genres of them all, but tower defense is really quite a simple concept. Defense Grid is no exception; you place towers on a path and/or grid to zap waves of invading enemies, using a variety of towers with different kinds of effects. The most important aspect of the game design revolves around the "cores". In the fiction, the cores power the grids used to defend the world from the aliens, and in gameplay you have to stop the aliens from stealing all 20 of your cores from the map. The more cores you have left on the map, the better your score. Keep all 20 cores, and you can earn a gold medal - lose all 20 cores and it's game over.
It's actually a little more complex than that. Like most tower defense games you earn resources ("credits") by killing enemies, and you use the currency to make more towers and upgrade existing towers. However, there is an extra twist. You actually earn interest on your credits over time and will generate money over time, but only as long as your cores are safely in the core housing. If the aliens remove a few cores, you will generate much less money, and if they take all of them, you will generate no extra income at all. This is a little twist on the genre that can make a huge difference, and really helps flesh out the game.
The key to Defense Grid is that aliens will spawn from one side of the map, follow a path to the core housing, steal the cores, and then walk to the exit point, which can either be a different part of the map from the entrance or can actually be the entrance. You only lose a core if the aliens carry it all the way to the exit point of the map. In the game's missions, this means that you will spend most of your time finding creative ways to make life as difficult for those pesky aliens as possible. Sometimes the aliens will have to use the same path to get to the cores and then get to the exit, which means focusing your firepower here is an excellent strategy. Also, some maps allow you to actually dictate the path the aliens take, meaning you can send them on winding twisting mazes with the hopes that the towers will destroy them along the way. And one of the key things about Defense Grid is that you use actual towers to dictate the paths; there is no wall building like in other tower defense games, so every piece you place on the map has a combat advantage.
There are a significant variety of aliens that will be trying to steal the precious cores. Standard aliens travel in packs and are relatively easy to deal with, but soon into the game you will see the more troublesome foes, including the Racer, a super-fast alien that speeds past your towers, flying aliens, which most types of tower cannot defeat, Lurkers, which are stealthed aliens meaning that they can only be attacked by towers at very short range, shielded aliens, who have an extra protective barrier that protects them from heat based towers, and even super-strong boss aliens, including one which carries an extra horde of aliens which is released when the main alien is killed, and the Juggernaut, the most powerful alien in the whole game. Each has its own distinctive look, so it's pretty easy to keep track of what's on the screen, and of course each alien requires its own strategy, keeping the game varied and interesting.
Of course, with such a variety of aliens to defeat, you will need a good variety of towers to defend your grid, and that's exactly what you get. The most basic tower, the Gun tower, attacks just one enemy with bullets, then as the story missions unfold you unlock different kinds of towers for different situations. After the Gun tower you meet the heat based weapons - the Inferno, which has an AoE effect, and the Laser, which shoots concentrated energy at just one enemy - and then you get longer range weapons, including the Meteor, an extremely long range AoE tower, and the Cannon, which is your long range DPS tower. You also earn Missile towers which can only attack airborne aliens, Combustion towers which shoot explosive around them and is great for dealing with large swarms, Tesla towers, which charge over time and release powerful energy blasts, Temporal towers which create a well slowing all enemies within its radius, and the Command tower, which increases the rate of credit generation and also reveals stealthed aliens within its radius, meaning they can be attacked by towers that strike from long range. And for things really get out of hand, you can use your Orbital Laser, which shoots an incredibly power strike from the skies to obliterate all aliens within a certain radius, but you don't earn any credits for using the OL to kill aliens, so it's really only used in last resort situations.
Did you get all that? Need a breather? Well, don't worry if that was all a little confusing, because Defense Grid introduces each tower really well and it's very easy to understand what they do and how you should use them. It really is a simple game in concept, but actually has almost all the depth and complexity of a full-blown RTS. You need to fine tune and focus your strategies for maximum devastation, and at the risk of making an A-Team reference, I just love it when a plan comes together. Damn, I knew I'd make an A-Team reference.
Let me get back to where I left off earlier when talking about the variety of the maps. As I said, there are 20 maps to play through, and the default story missions use the basic game mechanics, but each map also features a whole host of other modes to play. This includes a mode that is identical to Story missions except the aliens are tougher, adding an extra challenge to the map. There are also modes which completely change the gameplay. For example, there is a Poison Core mode, whereby you only have one core in your housing, but the core is poisonous, meaning that when you kill the alien carrying it, it travels right back to the housing and destroys all aliens that cross its path. There are also modes that give you a certain number of credits to work with, another which limits the amount of towers you can place on the map, and another which doesn't allow you to upgrade your towers. However the best of all are the Grinder levels. In most modes, you face waves of 10 to 30 aliens; in Grinder, you face 99 waves of weak aliens, meaning you have to plot your course carefully and survive for the long haul. It's actually incredibly entertaining, perhaps even more so than the core game.
So those are the key mechanics with which Defense Grid: The Awakening works, but it's not just gameplay and no narrative, although the story isn't anything to write home about. You are aided in the game by an artificial intelligence whose memory is restored over time, and together you are vital in defending the world from this returning alien invasion. You don't play a named character, and the story isn't exactly presented in detail, but it serves as a functional premise and a good framing device for the gameplay. Also, your A.I. buddy sometimes has some humorous lines of dialogue, which like a little bit of Hot Sauce just gives the game a little extra zest and flavour.
The sound design is pretty solid, but in truth, this is one of those games that you can play while wearing headphones and listening to something completely different and it will hardly affect your experience of the game at all. The sound effects for the lasers firing and for the explosions all sounds fine, and the music is unobtrusive but also varied and atmospheric. The one voice in the game, that of your A.I. friend, is pleasantly British, and there is a decent variety of dialogue. But really, the sound design is not a significant part of the experience. It's by no means offensive or annoying, but it just exists, and as I said, playing the game without the sound hardly changes the experience at all.
So that's pretty much all of the basis covered so I guess it's time to start wrapping up this review...except that there are a couple of things that are definitely worth mentioning. In the scheme of things, these parts of the game are tangential, but they really do enhance the experience in tangible ways. One thing worth mentioning is that these parts of the game are true of the Xbox Live Arcade version, and as I haven't played the PC version I can't vouch for their existence in that version.
The first one is that the game checkpoints frequently, and with just one press of the Back button, you can restart from the previous checkpoint. Not only that, but pressing the Back button multiple times takes you back to previous checkpoints, meaning that you can restart the mission from any of the checkpoints that you already reached. What this means is that if you were suddenly surprised by a wave of aliens and weren't strategically prepared for them, you can quickly reload from a previous checkpoint and rectify your mistake. This effectively adds a whole elements of trial-and-error to the game, which actually makes it incredibly satisfying as you revise your strategy over time without resorting to restarting the entire mission. Make a mistake in the final moments of most tower defense games and you have to do all the early work all over again and then kill all the weaker enemies until you get back to the part where you failed, but then you fail again which means you have to restart again and do all the early work and...well you get the idea. For such a simple part of the game, it's inclusion improves the game significantly, and can only be described as an example of design genius.
Second, and perhaps just as significant, is that while the aliens move pretty sluggishly across the map, and the game moves at a very slow pace, you can hold down one of the Bumpers to increase the speed of the game. This is another example of a simple yet totally genius idea, as it means that you can whizz past the easy early stages of the game, laying down your towers and earning your credits, but when things get difficult and time is of the essence, you can slow things down, do your work, and then speed you again to watch it all play out. It makes the game much faster paced, turning 30 minute maps into 10 minutes, which actually makes the game more addictive as you complete missions and progress much faster, which made me at least just want to start a whole new mission and do it again. In fact, I'd say I spent about 95% of my time playing Defense Grid with the right bumper firmly held down, as I had much more fun playing the game at high speed. However, with such a clever piece of simple design, you would think they might have had the courtesy to spare you from having to hold down the button constantly, at it does get a little tedious, sometimes even uncomfortable, especially during long maps. All it would take is making the speed a toggle. Is that so much to ask? In the scheme of things a small stain on an immaculate suit.
So with all that said and done, one more important thing to note is that tower defense is still ostensibly a niche genre. Your enjoyment of this game with correlate directly with your general enjoyment of other tower defense games. That said, if you've never seriously played one before, Defense Grid is so simple and yet so deep and engaging, and it reveals it's game mechanics in a progressive enough way, that beginners unsold on the concept of tower defense would do well by starting here. And who knows, maybe if you've played tower defense before and it never stuck with you, this one is so good it could cause a life changing epiphany. And if like me you are a fan of the genre as a whole, this is an absolute must own, because it brings hours of addictive and satisfying gameplay for a discount price.