geoDefense Swarm, the open-field tower defense game from Critical Thought Games, is now available in the app store. One of the most popular paid games, geoDefense Swarm combines a terrific graphical interface with surprisingly challenging gameplay to create a must-have, must-play experience.

geoDefense Swarm is quite an impressive game. With 30 unlocked maps spanning 3 difficulty levels, it may not seem like there is enough content to keep you playing long, but you’ll quickly discover that, without a solid strategy and the patience and foresight to see it properly come to fruition, you’re a dead man walking (or tapping, as it were). The easy levels in geoDefense would likely be considered hard levels in other TD games. Each map has unique features that will require specific strategies if you want to make it through to the end, including special tiles that can speed up or heal enemies. The gameboard is broken into a grid with hexagonal shapes throughout. These hexagons are where you will build you defensive towers, of which there are 6 kinds (blaster, laser, missile, slow down, vortex, and shockwave), though not all are available on each map. Each tower can be upgraded 7 times, slowly increasing in strength and effectiveness. Enemies will enter the map (at times, from multiple entry points) and attempt to make it across to the exit point (or points, as often is the case). From your starting cash, you must purchase and/or upgrade towers on the board. Money is earned for destroying enemies (creating bursts of neon pixels like those in Orbital), which is then used in creating or upgrading more towers. Your limited cash resources require you to build creatively and strategically. There is a specific number of waves of enemies per level and a certain number of enemies that you may allow through the exit point before the game is lost. When enemies reach the exit, a burst of red pixels blasts across the board, signifying your failure to keep the little buggers out. Allow too many through and it’s back to the drawing board. geoDefense Swarm does offer tips when you lose to encourage you to become a better player.

Graphically, the visuals are very appealing, employing a neon interface seen in many top-down space shooters. Information like score, remaining allowable enemies, and wave number are presented at the top of the screen, while available towers and a pause button sit at the screen bottom. While there is no background music, you’ll have only the shooting and exploding sound effects to stimulate your ears. You can play music from your own library to fill the void. The lack of a soundtrack was our only true negative for the game. Controls are simple, utilizing taps and drags to select and place towers, as well as choosing which to upgrade or sell. These were very effective and never required us to tap more than once to register our selection. Autosave upon exit is enabled, so there is no need to fear a phone call.

As if the difficulty of geoDefense Swarm wasn’t enough to make you keep trying again and again, OpenFeint is incorporated to track high scores so that you can see where you rank against all other players. There is also an endless level within each difficulty level, testing you to see how long you can outlast the enemies. Though there are many TD games in the app store, few are open-field, and of those, none hold a candle to geoDefense Swarm’s challenging AI. While most games with seemingly impossible difficulties tend to frustrate you until you quit, geoDefense Swarm simply leaves you feeling like you just need to tweak your strategy a bit and you can beat it. It never really makes you think that anything is impossible, just that you are coming at the problem from the wrong angle and you need to adjust your attack plan. At $0.99, geoDefense Swarm is half the price of its fixed path predecessor and an absolute bargain compared to the many other titles in the genre. Do yourself a favor and snag this 5-Dimple gauntlet before Critical Thought Games realizes that its worth so much more.

geoDefense Swarm gets our AppSmile 5-Dimple rating: