Year 2, Chapter 2
As soon as you start, raise the two flags (2/4) using WiLe then open the trapdoor. Shoot the chest in the middle to whack the floating ball and smash the wall to the left. Use WiLe on it to assemble a trampoline.
Shoot the small barrel with a flag on it. (1/4) Jump to the next platform. Shoot the next barrel with a flag, then shoot the goblin.
Switch to Hagrid then pull the chain. Jump across the old geezers then shoot the goblin again on the other side. Use IM on the pixies up ahead. Shoot the barrel on a corner to the right first, then use LuSo on the vine. Use WiLe to assemble stairs from newly created debris. The goblin will run away so destroy the last barrel to unlock the Blue Crest piece. Go up the ladder, raise the last two flags to get the Yellow Crest piece. Lift the purple crushing ball then connect it to the chains to the upper right.
Go through the gate this time. Climb up the ladder to the left then shoot the goblin. Pull the chain to release the bird and for the two bricks to fall down. Create a foothold, then shoot the middle cabinet to reveal the goblin's location. Shoot him again then jump down to the lower level. There will be a couple of pixies here that will raise the bridge, so take them out first to cross. Shoot the barrel the goblin is in and shoot it again to trigger the next story scenes.
You'll start in the hospital room next. Gather the studs you want then grab the character token Dobby by jumping on the bed to the left.
You can switch to Madame Pomfrey to do most of the work here since she has all the spells and she's immune to the mandrake's wails. You need to find ingredients for the cauldron. The bone piece can be acquired by using WiLe on the skull on the bed in front of the closet to assemble a skeleton. After its dance, grab the piece.
Next is the flower piece. Use the mandrake to break the glass cabinet with the flower inside. Use WiLe again on the student to the left to release a statue that will break the locks and open the door to the next room. Use the purple broom to destroy the cobweb in the corner. After that, another web with a spider on it will appear. Grab the spider piece then throw it to the cauldron to complete this chapter.
Draco (Quidditch) – In the hallway where there are pixies blocking the path, continue to the right to find the dark cabinet.
Open the locked chest before the bridge that was lifted by pixies. This contains a student in peril.
Green Crest piece – You need to spread out two wallscrolls using WiLe. One is located on the ledge above the chest with a student inside, the other one is located across the bridge. You need a Slytherin character (Harry's Slytherin Disguise will work) to wave at both paintings to get the crest. Make sure you don't shoot Dobby or else you'll get transported to the hospital. You need to do the whole thing again when that happens.
Madam Pomfrey – In the second room of the hospital, use CR to remove the lock on the machine beside the puzzle cabinet. Shoot it to get this character token.
Red Crest piece – Switch to Griphook (press RB) then open the safe to get this crest.
Follow the ghost studs again until you reach the main hall where you'll learn a new spell. For the first part, just stay behind the red line then shoot the dummies by targeting them and releasing the fire button. After a brief cutscene, you'll be in a battle against Draco. Immobilize him with your IM then shoot him. Repeat until he's defeated. You'll learn the new spell Expelliarmus and get a Gold Brick as well. Parseltounge will be unlocked as well as soon as you exit the room.
Exit the room and follow the ghost studs again until you reach the hallway with snake glyph. Press B to speak to it and for three snake pieces to appear. Use WiLe to assemble them on the pink stand to the left. The dungeon door will open afterward.
Go downstairs and examine the door to trigger a scene. Follow the ghost studs again and keep following it until a cutscene triggers and you find yourself inside the potion room. Like before, you need to find the three ingredients. Remove the debris to the left to reveal a pot containing a tentacle. It will devour the nearby student. Grab the hair piece left by the unfortunate student. Shoot the green, blue and violet bottles to pour their contents on the pot. A large plant will grow with a cherry piece. Grab it and throw it in the cauldron. The last green piece is located behind the golden door in the lower left part of the room.
Use IM on the pixie and throw the last piece to the cauldron. You'll unlock the character token Justin Finch-Fletchley automatically. Drink the potion and transform to Justin Finch-Fletchley or Hufflepuff Boy. Talk to the nearby painting to unlock the Polyjuice Potion. This will enable you to use any cauldrons you come across.
(Optional) While you're here, look around for some yellow bottles that release balloons when you pop their caps. There are four of them in the room. After transforming into Justin, wave to the painting to the left to get the last bottle. You'll be rewarded with tons of studs by doing this – which is a lot if you're not using the multiplier cheats.
Exit the classroom, then follow the ghost until you reach the hall with a cauldron. The ingredients should be readily accessible so grab them all and throw then in the cauldron to create another transformation potion. Go to the right and wave to the painting (Hufflepuff character required) to open the curtains. Grab the character token Harry (blue shirt) behind the staircase. Go upstairs and enter the door to the next area.
Use Hermione to open the puzzle cabinet, then assemble to pieces to form a safe that you can't open for now. Continue to the right then use WiLe to fix the leak. Continue to the right for a scene. Enter the room to continue with the story chapter.
(Optional) If you continue to the right, you'll find two pixies holding some pieces of the small pet tunnel. Kill them then fix the tunnel. Send Ron's pet to hit the switch. A floating pirate ship will appear and start releasing volleys of fire that explodes to several studs upon impact.