Some apps have a dedicated screen where as your start screen and other apps lets you jump right into action. From what I have experienced so far is that games mostly use the scenario with a start screen and not that many have the possibility to jump right into action. Some even have multiple screens before you get to the action.
Well I have decided to go the other way with my game. No code or nothing yet, just my thoughts. I will let the user get straight into action and instead have a action bar to give the user the ability to navigate to settings screen, hi-score and so far.
This means that I will try to target the design guidelines for Android 4 (http://developer.android.com/design/index.html). This would be a problem if I were to release the app tomorrow, but I think that we are at least one year away from release (have many other projects) and my that time the majority of the users have either upgraded their existing android phone if possible or bought a new smart phone.
Right now (http://developer.android.com/resources/dashboard/platform-versions.html) there are only about 3% on Android 4 or higher. The majority of users are on either 2.2 or 2.3 with a total of 86% on these two versions. In a year this will be totally different and my guess is that at least 60% will be on Android 4.0 or higher.