It makes very few changes to the formula found in the first game, but those few changes keep it from feeling stale.
Story-wise, the game picks up from where the first one left off, with Harry about to enter his fifth year at Hogwarts School of Witchcraft and Wizardry. The story stays remarkably true to the books and films, making very few changes. Harry's tale only gets darker and more volatile from here, yet the game still manages to successfully implement the silly humour typical of the Lego series where it's appropriate. It never feels too over-the-top, managing to blend the bleak outlook of the story and the daft comedy together without sacrificing the essence of the tale it's trying to tell.
Gameplay-wise, the formula is still the same as it was in the first Lego Harry Potter title, with very few changes made. You'll still proceed through levels based on parts of the story, exploring areas and smashing/manipulating as many Lego objects as you possibly can in order to find the way forward. Each and every level contains basic puzzles which you'll need to solve in order to proceed, mostly involving breaking and rebuilding parts of your surroundings. You'll generally have two or more characters at your disposal the whole time, with each character having their own ability, meaning you'll need to swap between characters if you need to use a particular skill. The levels themselves are designed really nicely, and feel a lot more varied in their appearance and setting than they did in Years 1-4.
Outside of levels, you can explore the hub world which once again primarily takes on the form of Hogwarts. Hogwarts has not changed enormously since the first game, but a few areas have been changed to lead out into different parts of the castle. The game also makes hub world additions in the forms of a street of London and some countryside which cannot be accessed until reaching a certain point in the game. You can also revisit Diagon Alley and the Leaky Cauldron in order to buy things such as playable characters and spells. All of these hub worlds eventually intertwine with one another, meaning you'll never really need to select an option on the start menu to quit one area. It helped to make the hub worlds feel like a part of one big world, something I felt the first game never quite managed as successfully.
One of the biggest appeals with the Lego games is their addictiveness. There are a lot of things to smash and manipulate, both in the levels and out of them. Smashing bits of Lego reveals studs, which acts as the currency in this game, and can be used to buy characters and spells from Diagon Alley. Collecting these studs can be surprisingly addictive, as can the need to collect absolutely everything the game has available, including character tokens, Hogwarts crest pieces and gold/red bricks. Each level and hub world may also contain parts of the scenery that cannot be manipulated by characters you have currently available, meaning you'll need to revisit areas and levels once you've found and bought a character that has the ability you need, such as dark magic or a safe key.
There are a total of eight spells to learn in the game; a few make a return from the first game, including Wingardium Leviosa and the Patronus charm. However, the inclusion of new spells such as Diffindo (enables you to manipulate red Lego) and Aguamenti (a water spell that puts out fire) helps keep the game feeling fresh due to the change in approach to solving puzzles. On top of this, the game adds in a new duelling system which is both simple and satisfying, in which you need to match the spell of your opponent in order to successfully take them down.
There are new items in the game that can be used, including Weasley Boxes and Spectrespecs. Weasley Boxes can be found scattered from location to location but can only be opened by a member of the red-haired Weasley clan. Spectrespecs enable the wearer to see bricks that are invisible, making it possible for the player to build with them. These items along with the new spells and minor gameplay tweaks certainly help to differentiate the formula enough so that it doesn't feel the same as Years 1-4.
One of the biggest gripes I had about Years 1-4 was the sheer amount of glitches, and while Years 5-7 is not completely glitch-free, it is nowhere near as bad as the first game was. However I did encounter a couple of stages in which I wound up having to restart a level due to glitches and that is unacceptable, especially taking into consideration the amount of Lego movie-based titles that had been released before this one. Another issue was the load times, which, while not terribly long, were still tedious.
Graphically the game is beautiful and charming to look at. Hogwarts has been brought to life incredibly well once more, as well as the other areas. The levels all look fantastic, particularly levels such as The Tales of the Three Brothers, which seems to match the artistic style used in the movie's depiction of the same scene, and a level set in Hogwarts past with the younger Marauders which uses a nice sepia tone to separate it from the present timeline with Harry. The music is utterly fantastic, which is unsurprising being that they are scores that came from the movies themselves.
All in all, Lego Harry Potter: Years 5-7 is yet another great addition to the Lego series. It makes very few changes to the formula found in the first game, but those few changes are enough to keep it from feeling stale. Collecting studs and collectibles still manages to be insanely addictive and the puzzles remain straightforward yet fun to solve. If you loved the first Lego Harry Potter game, it is very likely you'll love this one just as much, if not more.