Thanks for the report, this is indeed not supported at the moment, though we could pick it up and override the return code if Environment.ExitCode is different than 0. I am not sure if this will not break some edge cases though.

The alternative that you can use return 1; at any place in the top-level code of the script as behind the scenes it gets wrapped into method returning a status code.

if (Args[0] == "foo")
    return 127;

Console.WriteLine("done");

An even quirkier thing is that you can just place an int (or a method call returning an int) at the end of the script, and that gets converted into a status code too (though that only works at the end)

Console.WriteLine("done");
127