I'm far from an expert, this is just what I would change.
http://androidarts.com/pixtut/pixelart.htmFurthermore, there's a lot of pure black/white. Don't do that.
Reworked the interface while waiting for feedback on my own thread.
Ideally the top of the General settings would line up with something to the left to connect it and make it seem more like a whole, but I just closed photoshop.
By moving the interface elements away from the edge of the screen your game feels bigger, more open without the interface framing it.
It's also important to align elements to make them seem a cohesive whole. If you draw horizontal and vertical lines across the entire screen along the edges of your interface elements you'll notice the separate elements don't align at all, or barely not.
(the chat)