To unlock this achievement, you first need to rescue all 35 Stan Lee’s. There is one in each of the 15 story levels, one in each of the 7 hubs and 13 in Manhattan.
After you find all 35 Stan Lee’s, his character is available to purchase for 50,000 studs. Once he’s bought, select his character from the grid to play as him then hold
to change into one of three Stan variants. Simply select ‘Stanbuster’ in the top left corner to unlock the achievement.