geoDefense Swarm

The tower defense genre is really the genre that fits the iPhone the best. No matter how many FPS and RTS apps that get pumped out, tower defense is what the iPhone was made for. It is the only action game genre that really allows you to play for 10 minutes and then put the device down without losing hours (minutes?) of gameplay and a good portion of your patience. It's no wonder that some of the best games to grace the device are tower defense epics such as Fieldrunners, The Creeps!, and Sentinel.

With that being said, the thing that the genre really doesn't do well is manage the difficulty. It's not that these games can't be hard, but it really takes some heavy build-up to get there. Take Fieldrunners for example, which is an iPhone classic through and through. To beat a level completely you have to get to round 100 without letting too many Fieldrunners in. Rounds 1-30 are usually a breeze, but they also take about 10-15 minutes to accomplish. Once you get to round 30, things get tough until about round 60, when you have an impenetrable defense set up that'll get you to level 100 and beyond. Half of the fun that Fieldrunners provided was the fact that each level could be played into infinity, taking up hours of your time, but giving you a pretty good challenge from time to time. Does the average non-iPhone website editor have 2 hours that they can dedicate to an app? Do I even have 2 continuous hours to play an iPhone app? The answers are no and no.

Fortunately, my gameplay length concern was answered by the brilliant geoDefense Swarm (gDS). Instead of making you play just a few levels for seemingly infinite lengths, gDS gives you 30 levels spaced out over three difficulty levels, each of which require anywhere from 15-35 waves to pass, making them 10-20 minute affairs once you finally figure out how to beat them. The thing you need to know about gDS is that it is genuinely hard. I'm not talking relatively challenging, I'm saying that this game is hard. Being the cocky iPhone player that I am, I decided that the easy campaign wasn't enough for me, and decided to instead go straight for the medium levels. What a mistake that was, as I lost to the very first level about 20 times before resigning myself to learn the game through the easy missions.

What makes the game so difficult is that every level is completely different in terms of the design and your units. Each map is a basic square, allowing you to place towers on any place on the grid that you would like. Traditional tower defense strategy is tossed out the window because each map, except for a few on easy, have spaces that you can't build on, including spaces that speed up enemy units and some that even heal them. Aside from the level design, the guns in gDS are pretty standard fair, consisting of regular guns, lasers, rocket towers, a slow down gun, and a thump tower that does minimal damage in a 360 degree area. Each gun can be upgraded a total of 7 times before it is maxed out and converted into some sort of super weapon. The tricky part of the levels are that the weapons don't have fixed prices and some aren't available at all from level to level. Some levels will let you use slow down guns and rockets, while others will make you invest in laser towers that are heavily price inflated.

The graphics and sound in gDS are quite nice, although they may not be quite as good as the movie-like quality of Fieldrunners. The visuals are very Geometry Wars-esque, with neon figures exploding into fantastic displays of color. A neat inclusion in the graphics department is that each upgrade of each weapon has a different design, making upgrading that much more enjoyable. The sound, which I've heard people complain about for some reason, is perfect for the genre. While there is no in-game music, the sounds of each individual tower firing along with the explosions make the action that much more intense. My favorite touch though is when enemies get through your lines. Instead of just making a random noise, a robotic female voice reminiscent of SHODAN from the System Shock series calmly states how many lives you have left.

All in all, gDS is one of the best, if not the best, tower defense games on the iPhone. It's intensely challenging, the level and unit design is superb, and there are enough levels to keep you entertained for a long while. For the ridiculously low price of $0.99, just over the price of a single taco at Taco Bell, there really is no reason to not buy gDS.