I lied... it's a really boring one.
It seems a few people really couldn't get their heads around the controls, and configuring them so now gamepads are defaulted out like most games, so if you're gamepad inclined no mucking about needed. Keys are unchanged.
We've generally changed things to be a bit more consistent with controls too.
Also, embarrassingly, the game appeared as "Spacewar" in steam, and we had no idea why but now we've fixed that, it was a typo (really).
Hopefully our next update will be a bit more stimulating :).