Why I can only choose from 320x200 to 640x480?
The resolution is limited because the game is designed to run at at aspect ratio of 16:10 only. And I believe in smaller screens - like those on some laptops, this severely limits the available resolutions. We are working on fixing this, by creating a dynamic GUI that scales comfortably across multiple aspect ratios, and we should have an update regarding this by Saturday or Sunday.
Thank you for downloading the game, and my apologies for the issue, I will send you an update as soon as we have a fix implemented.