Yeah, the slow fade was essential for me. I messed up my first attempt, then did it my second attempt by quickly encircling the eye and hitting all the corners before it faded.
Ah! The eyes were very tricky for me too. Took me 3 tries to get the 100% so this does not seems too difficult IMO. But as the creator of the quiz, it's probably not something to take into account :)
the sudden death stats are very funny with this one lol like oh yes, this identical black square tripped up the largest percentage of people, good to know :') x)