LEGO Harry Potter years 1-4 is based upon the events of the first four Harry Potter films, which in some ways is why the LEGO series works so well because if you have watched the latter you get a basic gist of what is going on in the game.
Of course in the LEGO universe the cut scenes depict a familiar story but they have been altered slightly because let’s face it killing off characters or maiming in general is not going to go down to well with the parents (as the target audience is certainly aimed at the kids) however instead you get scenes re-gigged with fun and slap stick comedy alternatives.
Another reason for the slight change in plot from the film is that the game supports two player action so it will be difficult to play the fourth year if one of your characters bites the dust.
However we have to say from the off that despite its childlike persona the game is certainly going to take you a while to complete at 100%. After weeks of gaming we had only completed 54%. This is because there are gold bricks to collect, students to rescue and certain areas of the game that can’t be accessed unless you have either learned or purchased spells from the shops at Diagon Alley. Additionally the game provides you with the option to buy different students from the aforementioned shops, which again are used to unlock parts of the level that you can't access with the standard characters (i.e. Harry, Ron and Hermione Granger).
While we are on the subject of Diagon Alley you can also visit Gringotts which then opens up extra bonus levels.
In-Game
As with most LEGO games you can literally destroy a range of objects and then collect the fallen bricks (which can then be used to purchase items from the aforementioned Diagon Alley). This is a little less rewarding than the LEGO Pirates of The Caribbean Game we also played this month, as blasting objects with your wand doesn’t feel as satisfying as bashing them with a sword.
However you can re-build fallen LEGO pieces to build new objects and in-turn gain access to different areas (which provides puzzle elements to the game-play).
The developers also throw in additional ways to keep the game-play from becoming stale as you get to pick up mandrake roots - once you don a pair ear muffs first! - which can then be used to shatter glass objects containing vital pieces of LEGO for solving puzzles.
Or you have to find pieces of LEGO to stick in a cauldron so you can become strong and pull the chain needed to open doors. Additionally you can begin to learn light spells which come in useful for removing creeper tentacles that are blocking vital paths. So all of this adds to the puzzle solving element and is a nice touch.
Most of the levels take place in Hogwarts and the surrounding grounds so things can get repetitive, especially as there is also a lot of to-ing and fro-ing going on, but thankfully you never get lost as you follow the Ghostly “Nearly Headless Nick” to reach each destination.
Of course you do get to fight most of the bad guys that feature in the films, such as the Dementors and Voldemort. For the most part you get a standard wand spell to combat the enemies and several secondary spells which are more powerful or have different uses such as levitating LEGO bricks (as well as other students!).
There are also plenty of sections that need co-operation from your buddy in order to progress and again things become more interesting if you take on the role of Ron. For example he can produce Scabbers the rat which is needed at some points in the game to traverse pipes that are inaccessible by your standard characters.
Gripes & Summary
Despite the repetitive nature the kids will love the cuteness of the LEGO animations and how the story is softened to combat some of the 
harsh scenes from the film. However the biggest most signal annoyance of this game is definitely the camera angles! This leads to shouts of frustration as you think you have navigated a bridge properly only to see your LEGO character fall to its death (which results in you loosing collected LEGO pieces).
In the two player mode the screen does split when one character goes out of site from the main camera, but we found this distracting. In some ways the camera angles are better than the Original Indiana Jones game - which had no split screen and even worse camera angles - but in fairness the game is a few years old now and later titles have marginally improved upon the camera system.
In summary the graphics are good and capture the essence of the film well in LEGO format. The combat and traversing can be repetitive at times, but the developers have thrown in a fair chunk of diversity to keep things above boring and there is still plenty of longevity to be had.
