Why did they find it necessary to use an ARM to drive 12 LEDs and read one button? Surely they could have found a cheaper microcontroller to do that. (I didn't count the RST and ISP buttons in the upper left corner because they're presumably only used for debugging the board.)

As you can see, I was rushing when I did this guide. I'm planning to redo the disassembly next weekend and take landscape-oriented photos with better lighting and a white background.