Thanks again for your feedback, Hobcramwork! 1: In relation to the gold- Currently, it is entirely luck based (something I personally dislike, and will be fixing as soon as possible). Every thirty seconds you survive, you have a 20% chance of gaining a gold piece. One of my playtesters managed to get three or four gold pieces over a few plays, while I only managed to get one after ten or twenty! So that will be changed as of version 0.6, which will introduce a few large gameplay changes!
2: The skins aren't working for you? I've been testing my game for a while, and I've never heard of this as of 0.5. In fact, I just loaded up the game, and the skins are working for me. Is there a chance that you didn't have a high enough score before you went to the unlocks screen? If not, is there any way you could send a screenshot of your problem?
3: The boss fight was meant to be pretty hard... but it's not the end of the game. I plan on introducing challenges and most likely additional bosses that more of the story. Mostly, the final "cutscene" was really only there to get you thinking about what could be going on.
I'm glad you're having fun!