After you approach the end of the game, where Dumbledore will tell you to finish unfinished business and then attend the House Cup Ceremony, notice that each time you go outside and visit Buckbeak he will be a different color.
Calling other characters
If anybody is falling behind, press L to call them.
Defeating Dementors
Clear out the Dementors in the middle then go up to the Dementors that are sucking the soul out of Sirius and attack them. The health meter at the bottom will go down. Keep attacking until you defeat it. Do this quickly, as Sirius only has a bit of health.
To defeat the Dementors in the first stage (where you drag Sirius Black), do not wait until the Dementors are sucking the soul out of Sirius. Hit any of them that edge closer with Expecto Patronum. After a few hits, the first stage will be over.
The second stage of the Dementors is much more difficult. There are many more. Shoot Expecto Patronum at the Dementors (do not power up as Sirius will get weaker), and press A to charge at them. Break through the crowd in the back. Once you have a path cleared, go for the Dementor attacking Sirius. Power up until it automatically shoots. Remember to press A to charge and go faster. If you take too long the Patronus will die down.
Defeating Fire Salamanders
Make Hermione the leader, then use Glacious on them. They will turn blue. Then, use Flippindo and they will be destoryed. Use Glacious on the cracks or more salamanders will appear. Note: Use Flippindo quickly because the Fire Salamanders can still move.
Defeating Hinkypunks
You will first come in contact with Hinkypunks on the same level with the Goul. Hunkypunks are ghost-like creatures with one foot and a lantern. To defeat them, have Ron shine Lumos Duo in their faces. When they become solid and zombie-like, finish them off with Flipendo.
Defeating the fire armor
When fighting the fire armor thing when you just got Glacius, to avoid the shooting fire rocks when he opens up, stay directly in the middle. You should be able to avoid almost all of them.
Start with Flipendo until he opens his mouth, then use Glacius until he sort of explodes (this does not mean that he is defeated). One of his arms will come off. Use Glacius to put out the fire, then use Flipendo to destroy it. Repeat until he is defeated.
Defeating the Goul
On the "Neville And The Goul" level, after you have completed all of the tasks and have opened the chamber, light Lumos Duo in its eyes. Then, lead it into the chamber to lock it in.
Defeating the metal armor
He will try to spin around to attack you. You must dodge it, and when he stops, use the spell that grabs things. You must grab each of his four shields. When the shields hit the ground they will turn into monsters. Once you kill all four, he gets swords. He will stop spinning. Wait before you grab his head with the spell, because he will hit his swords on the ground. After he does this, grab his head and yank it off to defeat him.
Different dueling teams
During the school day, if you go to the Great Hall and start dueling, you will have the same team everyday. However if you turn off your PlayStation 2, restart the game, then go to the Great Hall, you will face a different team from a different house.
Find Goliath of the Giant Card Set
To find Goliath of the Giant Card Set, use Reparo on the broken vase on the sixth floor. It'll cheer up Glanmore Peaks.
Find Lady Carmilla Sanguina of the Vampires Card Set
To find Lady Carmilla Sanguina of the Vampires Card Set, let Hermione use Glacius on the fire in the Gryffindor Common Room.
Getting past Trolls
Throw a dung bomb by them and you can easily slip past. Another way to get past the Trolls in the north wing of the seventh floor is to use Hermione. Use the Glacius spell on the Troll to distract it then run away. It is not as easy as using dung bombs, but it will do the trick. If you are not careful you can still get caught using this method.
Gryriffindor ties and clothing differences
When you talk to other students, look at their ties. Everyone has a Gryriffindor tie, with the exception of Malfoy, Crabbe, and Goyle (whom have different ones). Also, there are only two people with their shirts out, which are Ron and Seamus, and with either Crabbe or Goyle, only one has a school jumper on.
Harry's Dad's voice
When you get attacked by a Dementor and it is stealing your soul, listen closely. You will hear a male voice yell "Lily! Its him run!" or "Lily! Take Harry outta here!", which we can assume its his dad telling his mom to get Harry to safety the night Voldemort came and murdered them.
Hermione in Boys' Dormitory
Go to the Griffindor common room as Hermione. Go to the door that leads to the Boys' dormitory. You will then be able to go in the Boys' room, while Harry and Ron cannot go into the Girls' room.
How To Get Fairy Wings
When you have to collect Fairy Wings as part of your homework assignment for Professor Snape you will get the chance to go to Hogsmeade (The Woods outside Hogwarts). When the fairies come out, use Hermione and cast the Flipendo spell (KNOCKBACK JINX) and if you hit them then they will fall to the floor. You then have to use the Glacius spell and freeze the fairies, then walk over and pick them up.
Invulnerability
At the main menu (with the D-Pad) press Up, Left, Down, Left, Right, Black, Black and White and you will be invulnerable.
Owl racing
When owl racing, if you fall behind rapidly tap B. You will catch up.
Seeing ahead
When you get Expecto Patronum for Harry, fire the spell in any direction and use it as a guide for seeing what is ahead.