Alt-tab usually works on the main menu but not in-game, in my experience.
Other people here have noted that the Steam cloud didn't copy their save, but this game doesn't use Steam cloud. If you want your save to be copied, you have to use the developer's own cloud feature. I have no idea whether that works or not because I haven't tried using it to copy a save to another machine or OS.
I tried opening my saved game from windows to Linux, but couldn't launch
Window mode isn't optimal
Didn't load my Steam cloud save unfortunately.
Works perfectly out of the box
Steam Cloud did not transfer my Windows save to Linux, touch screen controls works fine on Ubuntu
It opened fine, though slightly bigger than the window it displayed in, with dated Nvidia driver. After updating drivers to try to comply with minimum requirements, the game would not start at all.