There are 7 characters (sticky archer, assassin, bowcaster, bladesmith, sir nicks-a-lot, falling beard, and beastmaster) that no one has been able to find in a chest like they are supposed to. A lot of people have gone past wave 100 and not a single person has reported finding any of these characters. Please fix this or remove messages like the one that says, "The ghastly hydrake approaches! Find powerful allies like Fallingbeard to help defeat it!"
There is no way to buy the coin doubler, soul doubler or dragon mage once the starter pack and elite starter packs expire. You also can't buy charms or golden allies, but I'm guessing that part is intentional.
The bonus for completing wave 50 was ridiculously small. I got more gems and charms when I completed wave 40. For wave 50 I only got 5 gems, 1 revive and 1 peace charm. If my memory is correct in SvsZ I got 100 gems, 1 revive, 2 food, 2 tea and multiple charms since completing wave 50 is like beating the game because you've accomplished your goal of rescuing the princess.
Some other bugs I've noticed is that I've gotten the message that says I've unlocked Summon Lightning and the message that I've unlocked the peasant multiple times. This can happen if I complete a multiplayer wave and my iPad goes to sleep before I click on the OK button to collect my award.