Fun little survivorslike! As the others have said, it would be nice to be able to keep shooting by holding the mouse button instead of clicking again every time. Also, the health system doesn't seem to be working.
A nice way to improve the feel of a project (and that's quite easy in Unity) is to change the Unity default font. I personally like to use Google Font, and it's a really simple way to really change how "polished" your game looks.
Congrats on finishing a game for the jam!