Games offered through the Android Market are typically not that large. Sure there are some games that require around a gigabyte of storage to house all the data files, but most games are good about staying under 30MB. Google is now letting developers place apps in the Android Market that are up to 4GB in size.
If you run into an app like this, the APK file will still have a maximum size of 50MB. However, developers can attach two expansion files to the APK that are 2GB each. You’ll be able to see just how large the entire files is before you download it. That way, you’ll be able to make space and make sure you’re connected to a Wi-Fi network before starting the download.
Depending on how old your Android device is, the large downloads will be handled in one of two ways. They will either download automatically from the Android Market, or the downloads will wait until you start the associated app for the first time.
The 15 minute refund period after purchasing large Android apps won’t start ticking down until the all of the files have been downloaded.
Via [Android Developers Blog]