There is a known issue that the game takes very long to load when built to an APK.
In the launcher it is nice and quick, but in APK it takes about 5-10 times longer to load. I emailed Ludei a few times about this, and the only thing the think might cause it is the way that android loads assets. They're looking into a solution, but for now there is nothing to do that can make it faster. I made a little intro video animation thing run on top of the loader layout in order to distract the user while the game loads in the background.