You don't seem to have packed all the necessary files with the game for it to be able to run :(
When distributing a godot game that is exported to windows/linux, you need to also include the .pck file that the exporting creates, as that's where all of the resources and such are stored. If you wanted an all-in-one .exe, that's possible with godot as well, but you have to set the appropriate option, "Embed PCK" under "binary presets" in the export menu.
The godot docs for all of that are here: https://docs.godotengine.org/en/stable/tutorials/export
I hope you're able to & allowed to correct your technical problems before the judging period is over :)