I'm pretty sure roughly half the screen height was occupied by an image that other Unity based games don't have. I'm not saying you have to fix it, you owe me nothing, but it sounds like something you should have control over. I guess that's yet another reason for me to avoid Unity.
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The launcher window doesn't fit on my screen and can't be resized, so I can't even launch the game. It probably won't work for me (Unity-made Linux versions don't like non-Ubuntu distros), but you might want to fix it with other OSes in mind.
I'm on Arch Linux. It opens up in a fixed-size window that's bigger than my screen, so I can't see everything. (That's still better than most games work on non-Ubuntu distros, so props for that.)