Is it possible to improve the shadows in the game?
 

The shadows from the palm trees has blocky edges, which I find annoying since these shadows move around on the ground.

Is there perhaps any way to make the shadows more refined?

There seem to be only two options for the shadows and I could not improve it. I enabled "soft shadows" but noticed nothing different about the shadows, and was not told to restart the game or anything else.

You can switch dynamic shadows to static so they won't move AFAIK.