Doodle Jump, by LimaSky runs only $.99 from the iTunes Store, quite a price for such a fun addictive game. Some may note the similarities between this game and PapiJump, but they are certainly different. Using the accelerometer feature of the iphone one tilts the phone back and forth to move Doodler, the green alien with a snout much like Q'bert, through heights of green bars, moving blue bars, brown bars that break, and white bars that can only be bounced on once, trying to get up to, well I'm not quite sure what you are trying to get to. The goal as best I can tell yet, is to go up, and as high as you can.
There are springs to help boost you further upward, but you must beware of creatures that are on screen waiting to destroy you. You can try to avoid these creatures, a not so easy task, or use your bi-directional shooter (your snout) to blast these characters away by pointing on the iPhone or iTouch. At the same time you must beware of black holes and space ships that suck you up into them, killing Doodler. A non-complicated game with all the attributes that keep you coming back time and time again for more game play. I highly recommend this game for its price and addictive play.
There are some problems with Doodle Jump on the iPhone 3GS, in that Doodler could go in slow motion. If this happens, kill Doodler (poor guy), then press menu, and play again. This does make play normal again until the developer releases a fix. Lima Sky is aware of this issue, and I was given this workaround through their email support. You can also follow them on Twitter (@LimaSky).