Hello Burvey I downloaded and played your game and I understand that core mechanics are in place and you have a nice ground for any other improvements or content additions in future if you so wish.
The only thing I can advice would be on what people call polish, firstly, as adviced by friends above, in the interface design. Though if you ask for specific information, I would not be able to deliver as I am not any sort of artist. But googling for interface design may be a start, as well as asking for specific help on the forums. But even before all these, you should have a clear design goal in your mind - if you don't already have one. Like a color palette, a standard system for icons, placement... I understand you are targetting handhelds, so character sizes, icon/button sizes all come into consideration here. It took several seconds and attempts to understand that I had no tokens and thus I am unable to upgrade my skills, even though token amount indicator was conveniently placed just because it's not correct size and/or color. The token amount is the most important thing in that screen (upgrade shop) so it should be the most noticable somehow. I would also suggest to move away from the edges of the screen a little bit more for everything that is on the screen. Not much, but some.
Of course it's better if all these support a master theme. ie you can go for sterilized/facility look and feel of Portal games, or steampunk look, or just cartoonishly cute looks and feels.
Next up is sound and music and you are almost done. Currently there is a lack of rythim in the game, something in the background that needs to tell the player something is happening or nothing is happening at all. Like a rythmic music that is increasing the tempo as the timer runs out (if there is a timer that is) or just a looming sound like a cave echoing that feels like the game is waiting for input from the player. Of course all these sounds and musics should be in coherence with the theme you selected first.
I am sorry I just talked (typed?) alot but your game looks so fundamentally complete - or ready to completion - that may have been exposed to some A.314/excitement :)