Here are several photos from Google developer advocate Chris Pruett's Google I/O 2010 panel on developing games for Android. Looking at the slides will give you a better understand of the challenges Android developers face. In addition to developing for a relatively new platform, Android developers have to contend with multiple versions of the operating system floating around on different hardware (various screen resolutions, trackballs, d-pads, keyboards, etc). Optimizing for the latest and greatest version is all well and good, but considering that a large portion of the phones are running older versions of Android and the input options differ from phone to phone, games have to be scaled to work for all kinds of users.