Well I was sick,so I wasn't going to work and played the demo 100+ times,note that,week after the releese i stoped playing.However the last few days,while I was watchng movies and stuff,I played the demo again,it was the time that everyone knew about the nugget mission,I tought,yeah I havent played like for a week so I will never get the nugget.Yet after the second time after,that week I got the nugget mission,wich i believe is date,like time,
based.It is just my speculation however.Also I don't believe that soft resset works,because every time that you play the demo,data is saved,also every time the scenery at the begining is different,for example one is fire the other is water.When you soft reset,I guess it is not working.Maybe the time to unloch the mission is set like some random number based on you serial code number you registered for the demo or something.Because the third time a friend of mine played the demo there were the secret misson.