I went through it a couple more times, and while I reached the "you are brilliant" screen, I still couldn't figure out what is meant here by "cheating" or "the trick". On the last task, where there are several instructions to remember, I tried just leaving it for a few minutes to see if there was a time limit, but there didn't seem to be.
Were you cheating by opening up the quiz in a second window? I didn't have the patience to do that... quicker just to memorize the instructions.
I did think it was slightly out of character that the last task doesn't say "Press" or "Don't press" the buttons - you have to infer that they want you to click the described sequence.