So I downloaded and have been playing since I left my first comment - This thing slaps, dude.
Some suggestions; give us the ability to turn on or off the auto-upgrade everywhere it's available, sometimes I want to focus on one color over another but I've since turned on the first one.
Show us how many diamonds we would earn if we were to exchange. Show us/tell us/prevent us from exchanging gold before silver, as we'd earn gold if we exchanged silver first.
More audio options, if possible.
All in all, really great dude. You could slam this thing on Steam for $1 and sell quite a few copies.
If you're interested, I'm a VO artist and would love to provide some recordings for you. Just a little plug at the end. :-)