The Google Play Store is a nightmare for smaller developers. Unlike every other app platform I can think of (including Amazon's) which just send you nice tidy royalty payments, Google expects you to handle the sales tax for each and every customer, everywhere in the world.

And yet virtually nobody talks about this. I'm quite certain that any developer without an accountant is either getting it wrong or ignoring it completely. This is the reason that if I release a game for Android, it will only be through Amazon.