Check up on Boozer

Purchase an upgrade under the Performance, Visual, and Paint Categories for your bike

Make a delivery to Tucker or Copeland

Upgrade either your Health, Stamina, or Focus for the first time

Get out of Crazy Willie's

Turn the sound down to 0 and music off in the options menu whilst in the library

Defeat 10 enemies with a Muggle character

Defeat the mountain troll, using Quirrell

Destroy 50 Devil's Snare plants

Buy every version of Voldemort (Quirrell/Tom Riddle/Voldemort)

Unlock all Animagi

Rescue all students in peril