To get auto completion for C# in Emacs install OmniSharp. To install OmniSharp install .NET targeting thingy then try to build. Then discover that there's some call to some kind of weird ass new powershell 6 method and try to install newest powershell. Figure out that to install newest stable powershell you need to download a few zips from MS and run powershell scripts in them as admin.

Windows is improving, it's becoming more like Linux. :P