Here are some example numbers from cooking and packaging TappyChicken for iOS in the 4.0.1 branch.
This is listing numbers with an executable that has the symbols stripped.
The overall Shipping IPA is 43.8 MB uncompressed (34.8 MB compressed), which breaks down into:
3.9 MB - Loading screens and icons (about the same compressed)
25.5 MB - Executable (never compressed)
We never compress the executable since it is encrypted when uploaded to the App Store and will not compress at all there.
10.6 MB - Engine content (4.8 MB compressed)
3.7 MB - Game content (0.7 MB compressed)
The executable is never compressed and the icons/screens are already compressed, but the game and engine content compresses quite well.
We will continue to work on reducing the amount and size of required engine content over time, as well as look at optimizing the executable size.
The loading screens and icons are
.png files that you create; you can provide fewer variations (Tappy Chicken has one for all the devices) or use simpler icons to reduce their size further.