Completely mouseable (with limitations described below).
OSK doesn’t seem to be usable.
RMB to set blocks, Drag LMB for rotation of structure.
Enable Viacam headmouse does not offer a function that would allow to drag the mouse with the right button down.
First start is in full screen where you have to create an user account by typing in a valid email address. There is no way to leave the game when there has not been created a user account, there’s simply no such icon.
There is no way that I have found to enter the game options before the account has been set. After that the game can be switched to windowed mode. I have not been able to locate an ini-file in order to change the fullscreen/windowed settings before the first start.
Demo available on Steam.