Thanks for adding for Linux!
I can't select "new game" from the menu. ;-;
I don't think it has to do with Distribution (Ubuntu) and GUI (mate). I can borrow here at home other computers that have Linux and test.
But I don't have Ubuntu, the closest is Debian.
Edit: I tested it on a pc with Debian and one with Arch, both had the same error. Maybe I'll create an Ubuntu mate live-cd to test.
But I don't think the problem is the distributions.
I already tested it running via Wine, the same problem occurred, but when I changed Wine to another version (if I'm not mistaken, 6.10) the keys worked but not the sound.

Sorry for the gif quality, I had to compress 17mb to 3mb. XD
This one is from Arch Linux.
As you can see, the other options work until I click "new game", after that, nothing happens.
I really have no idea if any Unity lib is missing for it to work...
I'll do a search, but I don't know if I'll find anything about it.
But I found it quite weird, because so far it has only worked on Ubuntu. And this is the first game that had a problem like this to me.
From what I've tested now, I realized that it might not be the input problem, as it recognizes the mouse and keyboard before clicking "New Game", after clicking, it remains on the menu screen and the keyboard stops working. And the options work, only the "new game" and "load" that don't work. I tested the keyboard settings and I can change the buttons.