In every level there is a red parcel which is hidden. When you find a red parcel take it to the grey and red postbox hidden nearby (some postboxes must be assembled first). Drop the parcel in the postbox and when you return to Barnett College enter the middle door on the right side of hall to enter the mail room. You will now be able to purchase the extra bonus that was unlocked by that parcel.
Secret Library EntranceAdded 16 Feb 2011, ID #3889
This hidden entrance can be accessed by going to the artifact room which is to the right of the stairwell. When you step inside the artifact room there will be a big hole, go to the railing with any character and jump over it. You will then be at the courtyard which is a quick and fast way to get to the library.
Characters, items and effects for the game are enabled by entering the following codes on the blackboard in the Math classroom which is behind the 2nd door on the left in the main hallway at Barnet College. When a code has been entered the corresponding option will become unlocked at the 'Extras' menu where you then have to buy it. Cheats unlocked like this can be turned off from the 'Pause' menu.