The setup is simple: A comet has hit Earth. This comet brought a new energy source, toxium, with it. The debris from the comet slowly removes any evidence that the sun exists, causing Earth to turn into a world of perpetual darkness. Mankind discovers that toxium could be their last hope. But, as usual, there’s a catch. Prolonged exposure to toxium turns you into a crazed zombie.
The single player campaign has ten unlockable missions but, since most people will cut through those missions like they were hot butter, most of the time you’ll be defending yourself from wave after wave of zombies until your base is overrun in the survival mode.
In order to battle the seemingly infinite amount of zombies that come towards you, you must build turrets. In order to have turrets, you need money. Unlike almost all tower defense games, you don’t get any money from killing enemies; you get it from mining toxium with refineries. You must defend these refineries from enemies, which brings another factor into the game: light.
Variety is the spice of death. Sadly, death isn’t as spicy in BioDefense as it is in other TDs (such as PixelJunk Monsters). With only being able to choose from only a missile launcher and machine gun tower, I was very disappointed. In my opinion, this was one of the few things that didn’t settle right with me. Hopefully BioDefense will follow the trend many other iPhone games are beginning to follow and produce some DLC and patches.
One patch that would be nice for the non-adult gamer would be a "disable gore" button. Puddles of blood are left where slain enemies once were. Some may consider it a little too muchblood.
Even though the game’s cast of enemies doesn’t disappoint, it was still boring. I say this because there are only ten campaign missions (with the first few serving as tutorials) and a survival mode. Both the campaign and the survival mode use the same exact landscape and map, making the game visually boring. After playing on the same map over and over, you’ll start to wonder why you’re playing at all. The worst part is that the redundancy of BioDefense wasn’t even the biggest disappointment; the graphics were.
The color of the entire landscape was pretty bland and boring (all brown with occasional green spots). All the enemies, though variety-filled, lacked any type of interesting or aesthetically pleasing character designs, the only exception being the whale.
After beating all of the missions and surviving 35 minutes in survival mode, I have come to the conclusion that BioDefense is most easily compared to puppy love. You love it initially, but slowly grow tired and bored of it and finally realize it’s best if you lay off of it for a while. For the small price of $2.99, I’d say go for it. I’m sure it will provide some useful entertainment…unless you’re over 12 years old. If you are over the age of 12, I’m not saying don’t get it. I’m saying you might want to save that $2.99 and put it towards a 5-dollar foot-long at Subway.