Starting the game windowed and moving it will cut off part of the screen, or most in this case, game runs and works fine except that you cant see it.
Yes, a long-standing known issue. As you can imagine it has really low priority in fixing though. Eventually we’ll get around to it. 
Will it be fixed for the steam early access release you have planned in the vaguely near future (cant remember how many updates we are away from that).
If it’s a deeper problem with the current game engine then we won’t spend time on that (we’ll switch game engine eventually). If it is easy enough to do now then yeah, we’ll fix it for Early Access.