Das Spiel lässt sich nur mit dem Task Manager schließen.
The game can only be closed with the Task Manager

k

Is there an inventory, call keyboard

You need to go back to the title screen, to exit the game. Dumb, but it is what it is. Or save and alt+f4.

Don't forget about the "Pause" menu. You can use it to exit to the title screen, where you can exit the game. It's hard-binded to the Tab key (you can't rebind it).