Can't really play it with mouse, sadly, since the player only looks up and spins around indefinitely without using the mouse or keyboard at all. The only game I have this issue in also. I'll try if using a controller works now.
EDIT:
Tried it again, this time with PS4 controller (I know it's probably not supported) and a 360 controller. While the latter does work, the spinning issue persists and has such a force I can barely do anything with the 360 controller.
Sucks I can't try this experience out like everyone else, but if you manage to fix it, I'll gladly try again.
And seems quite a few Unity games can/did suffer from this problem in the past, according to Google :(
And last but not least, thank you very much for offering it for free for a period of time. Much appreciated! :)