At one point I had a thought that I could vary the time between asking the charlieplexed buttons and add a piezo buzzer to one pin to get some noises out of the little handheld. But then you would have to have sound all the time, because you want to scan the buttons as well.

It would make much more sense to have the buttons connected via a bunch of resistors to the ADC, so you get free pins and a way to add a buzzer. The project I named in an earlier log is a way better basis to do so. 

It was fun to solder up the prototype and build a charlieplexed "keyboard" for the first time, but programming a game for it wasn't really on the time table sadly. I enjoyed the positive feedback from everyone on social media though and might think of something at a later point. Thanks for having this contest, hackaday people!

Hehe... just noticed the countdown said "since" and not "until". Anyways, nice to add some thoughts afterwards then!