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Serpents is an iPhone remix of the classic game Snake. In Snake you would simply guide your snake around the map, eating different thing and trying not to hit your own tail or a wall. There were other sneaks that you would have to kill at higher levels by forcing them to hit you or to hit the wall. You gain points for getting larger, surviving, and of course eliminating your enemy. Serpents isn't that much different then snake, except your goal is to just eliminate the other serpents.
You control your serpent by moving the iPhone around. It's all accelerometer based and can take pretty sharp angles very easily. Your serpent grows over time, not by any other means at all. That leaves you with the goal of survival until you become big enough to actually choke out your opponent. If you crash into the other serpent at any time or a wall, you're instantly dead, so you really do have to be careful.
Even on the most basic of levels, your opponent is still going to be pretty crafty. You'll need to take corners harder and be in place much more strategically then you would think, but it will train you to be more aggressive in the higher levels. Use the build up time to get control of your serpent and before you actually go in for the kill, and remember that you can unfortunately kill yourself with your tail.
This is a great game that utilizes the accelerometer very well. It gives you a better grasp of how fast paced you can actually get, involving you turning your iPhone just to cut a corner as fast as you can. If you've got time to kill, then definitely give it a try.