Cool graphics, but I think the game doesn't support 21:9 monitors though.
Here's what it looks like. I tried both version. Same problem.
Viewing post in Snake Civilization jam comments
you can zoom out with the mouse scroller (I'm pretty sure I mentioned it in the "How to play" section, didn't have enough time to add a tutorial) (maybe you did zoom out and there are some other problems?)
overall I didn't make any specific support for any type of monitor, but if you press F11 I'm pretty sure it should adapt somewhat automatically, although UI might look a little off.