1. You have to log in - why is this page not public?
2. You have to provide additional data like birthday, mobile number etc - why's that? Looks like somebody is keen to collect data of the users...
3. You don't get a final result after completing the test.
Well, point 1 and 2 can be easily "solved" by using some throw-away or fake-account data, but point 3 makes the test pretty pointless for a "just for fun check of my skills" test.
Regarding the questions: some were ok, kind of, but the choice of topics is kind of narrow and there's a bit of redudancy in a couple of questions. Please some of the questions are just about getting the sense behind extra complicated code snippets which (hopefully) nobody will ever write this way.
I may be ok the take the challengefor Belgian citizens to grab a price, but for none Begians I'd say it's pretty much a waste of time PLUS you are forced to leave some personal data.