Three things I could rant about:

1. I forgot that the Arduino is 3.3V and 8MHz
2. the OLED displays I once bought had no reset circuit - fixed by adding a 10k resistor and 100nF cap, see: http://rayvenn.alnet.com.ua/2013/08/crius-oled-display-fix/
3. the mounting holes of the pcbs are designed off center from the joystick - fixed case with dremel