The game was made using the Monogame and Nez frameworks, so I'm basically enginedeving, so a lot of things are rough around the edges right now.
Monogame does have a way to "publish" the game which I believe will allow you to run without installing the .NET runtime, but I wasn't able to get it working yet (it kept throwing errors).
Points 2-5 are good suggestions. I actually had 4 and 5 implemented at one time back when I was using Unity, but haven't re-implemented them in the new framework yet.