First, great login page. The design is nice and the purpose is clear. My only issue on this page is that everything is in English except for the Feedbackseite erstellen button. I used Google Translate and found out that it means "create feedback page".
Why is that in German?
Next, when I tried logging in with just the email it returned a server error. I tried again using the name test and that worked. It should be clear that you need to enter both and if name isn't entered it should return a message saying it's required rather that returning a server error.
The next page provides the links to share and administrate. On my mobile (Samsung Galaxy SII) it doesn't let me select the text to copy the link. It should be selectable or be a clickable link.
The submit feedback is great, but the fields don't allow spaces; only single words, otherwise no issues submitting.
The admin page is perfect.
Interesting concept that, with a few minor changes, could potentially take off.