Of course this won't work.
You need to adapt the email template for the detailed admin notification, which is where you can use YOUR question code. {code} is just an example that I gave. If you question code is 'hiddenquestion1", then you will have to insert {hiddenquestion1}, for example. This only will work for certain questions. Questions that have subquestions will need a different approach to access the responses of the subquestions, e.g. {questionscode_subquestioncode}
I recommend to read the manual about expression manager / script to understand how to build your own report in the email template.
Currently there is a specific code that includes all types of questions. But with expression manager you can decide more specifically what you want to include and how you want to include it into the detailed admin notification.