LEGO Harry Potter Years 1-4 is based, very loosely, on the first four books in the Harry Potter series, these being Sorcerer's Stone, Chamber of Secrets, Prisoner of Azkaban, and Goblet of Fire. It is neccessary to tackle them in order, not because this makes more sense of the storylines but because the game won't let you do it any other way. You are however supposed to be familiar with the baisc outlines of the Harry Potter tales; they are loosely connected.
Most of the game's advancement is through fetch quests, not too heavy combat, puzzle solving, and as you would expect in LEGO, collecting the bits known as studs. You have to guide Harry and friends through all sorts of environments facing various evrents and landing in some tricky predicaments.
Controlling the game is much better using the stylus than by the D-pad which has a very poor directing action. Touching items and people with the stylus allows for conversations and exploring items in the environment or to cast your standard attack spell. Some spells require simple problems to be solved. Also, you can, at some points in the game, play a chraracter other than Harry. Because the game is aimed at a young audience, failing a task or dyingand and such like, doesn't usually result in frustration; you can normally try again.
The graphics are good for what they are but with the occasional jerkiness, and the voice acting is good and there is not too much of it to be annoying.
The game’s lack of freedom may put some people off, but on the plus side you can always double-back to earlier stages once you’ve completed them to unlock all sorts of goodies. There's a lot going on and kids will probably not mind the fact that the story is not accurate to the original books. Hours of good entertaining fun for youngsters.