Sadly, I'm one such sucker that isn't satisfied until I have checked every last corner of a level for collectables (it's a curse, I know). Thankfully there will always be one of the Hogwarts ghosts patrolling the school's corridors, heading in the direction of your next objective. As an added bonus, these characters drop special ghost studs that rack up for extra achievements. So if you want to just get on with the story, or your memory of what happens next in the book is a little hazy, these supernatural citizens become more than a little useful.
You'll usually play as Harry, with the likes of Hermione, Ron, Hagrid and even Madame Pomfrey available to switch over to at the touch of a button, depending on the party. The various characters carry unique items and abilities, such as Harry's invisibility cloak, or Ron's pet rat, Scabbers, who can negotiate small tunnels to collect objects and unlock sealed entrances. At the very least it encourages you to use someone other than Harry each time, and it's always amusing to see how the different students react to given situations: Hermione, for example, can barely stay on a broom as it bucks and turns in an attempt to boot her off, while Harry is naturally something of a pro. Don’t be surprised when you get to the end of the game and find that you're only around 50 per cent complete. If you really want to find every last item then you'll need to replay levels in Free Play mode, using the unique talents of the unlockable characters to reach previously inaccessible areas.
Upon completing each level you are given the option to continue straight on with the story or to head back to the Leaky Cauldron, with access to the famous Diagon Alley. Here you can spend your studs on bonus material such as new spells and characters. I personally recommend purchasing the big head hex and then firing it at your friends, resulting in their ballooned bonces hitting the ground, temporarily anchoring them to the spot.
It's things like the big head hex that make the two player co-op mode so much fun. It's a tried and tested element of the series, something that any Lego game would feel incomplete without, and perfect for the Harry Potter universe. Many of the collectables require a bit of teamwork, perhaps with one person on a floating platform while the other charms it to move around the level. In short, it's nothing that we haven't seen before in the Lego titles, but it remains a vital part of the gameplay. If you have the opportunity of playing with a Potter-savvy friend, you should absolutely take it - this is an experience that needs to be shared.
Sadly, the slightly bizarre split-screen format returns from the more recent Lego games. Here the screen's dividing line rotates to accommodate you and your friend, depending on where you both are within a level. While the constant shifting is rather jarring at first you will find yourself warming to it, but it would be nice to have the option to switch it off, requiring you and your buddy to stick together - that's what friends do, right? Regardless, this is the kind of co-op game that will have you forever shouting and laughing with your mates as you help one another out, or screw each other with bulbous heads and trip jinxes.
Everything is a challenge, everything does something, and there's never a moment when you can't interact with the world around you in some way. Objects will come crashing down as you freeze and shatter troublesome Doxies, opening up yet more tasks for you to complete. Jumping on a sofa might spit out a student stuck inside it, or perhaps reveal a character stud, unlocking another of the 160 playable students, teachers, Death Eaters and much more. Not only has Harry Potter and Hogwarts School been perfectly captured and recreated in Lego form, but four entire novels of adventure are contained within its walls. It's been boiled down to a potent, magical concentrate - one that will entrance children and adults alike. Lego Harry Potter: Years 1-4 proudly lifts the trophy as the best in the Lego series... until you smash it for more precious studs, that is.