A-ha! It was my old controller giving up the ghost, finally. Plugged in anew one and yes, it works!
Great work, but PLEASE add controller support! The last arcade game I used a keyboard for was Space War/Computer Space back in the 70's!
This is lovely work. I wrote a short review here: https://fanboydestroy.com/2016/10/12/just-feel-a-little-indie-action-on-hump-day/