Hi!
I am aware of this, but I'm not sure how to avoid it. I can tell you the game is not a virus (feel free to run it through VirusTotal).
2FoamBoards is probably right, I think it being a custom engine is to blame. The .exe is fresh out of Visual Studio and this not signed in any way, which may be the issue.
I'm glad you were able to play it in the end! Hope you enjoyed it!