Umtali, I myself would have had some very embarrassing ID's on Johan's challenge, but it was a very good challenge.
When the challenges started may years ago it was meant for two things that it has absolutely achieved. The first was for fun, but the second was to enable people to learn.
Micetta is a good example. Incidentally I just deleted a few PM's from back in 2010 tonight (yes i don't get many) and I checked some of the participants answers then who are still participating today. Micetta as an example, has extended her knowledge unbelievably over these years, without probably having seen many of these birds in real life - so goal 2 met! (BTW - I give you a deep bow, Micetta
What made Johan's challenge good is that he got everyone to think wider.
The duck was a humdinger - but the fact is when going out birding you will encounter one of these at some point - You will now probably remember this challenge duck for a long time and so will think of this when trying to make an id - so you have learned
The feet again was tough, probably with about a 50/50 of getting it right if you did not know what to look for. My guess was wrong btw, but I learned a few things about the feet that I did not know, and in some cases this type of finer detail will clinch an ID when out birding. You forget the birds you had right, but the details of the wrong ones remain with you much longer, and jump up to memory when you see the bird while birding.
Awarding half points is up to the challenge master. In the time that I ran the challenges weekly I was much in tune of who each participant was and their skill levels, and so the rookies got many more half points for correct family or close call on species. However the challenge should never be a competition with the other participants, but a personal challenge on improving skill, and although I agree a half point might be encouragement, it should make little difference in enthusiasm.
Lastly a long time ago it was decided not to give the correct answers when giving the challenge score. The main reason for this was that often this lead to discussion in the thread, either giving the answer or giving the alternative possibilities, spoiling it for those who enter later in the week. now we rather have discussion like this one, once the answers are revealed.
Thank you for the positive criticism, it is always good to think about, and jot down, the purpose of the challenge every once in a while, to remind both players and challengers of why we participate.