A must-play if you're a LotR fan
There are 18 chapters including the Prologue stage that work as any other LEGO game before: you collect studs, which act as currency, along with minikits that build models of several places or characters from the movies. You also collect treasures and mithril blocks that you use to build mithril items. There is a Story Mode and Free Play option on each chapter, allowing you to use characters you have unlocked on levels they originally were not present. For example, having Frodo or Sam on the battle of Helm's Deep of fighting Shelob the spider with Legolas. This is required of you once you finish the Story mode, as many minikits and treasures are only accessible through the unlocked character's abilities.
Between chapters, Middle Earth is available for you to traverse with your character. there are NPCs everywhere with fetch quests that will give you mithril bricks or red bricks for your troubles. During the story mode run (which you should finish before going into Free Play) you get to a point with characters that you cannot go forward unless another party finishes certain chapters. For example, Frodo and Sam cannot get into Mordor until Aragorn goes to The Black Gate. It's a fun thing to switch between parties and reenacting the movies in order. The LEGO charm is ever present; several scenes that would be scary to children are lightened by funny visual gags throughout, making it more approachable for kids. The multiplayer component is like the LEGO Batman 2 game. you can have a second player split the screen and help you finish the chapters and grind for studs. You can drop out that second player at any time. During Free Play it is great to have 2 Legolas available on screen if both players are a fan of a character.
For completionists, the game may take over 20 hours as you have to grind for studs in order to acquire red bricks and unlock everything. Getting to 100% will take its time and you will play several areas many times, but the trophies/achievements are attainable. The best trophy/achievement is "One does not simply...", a popular Internet meme. It's very funny to see it come up when you do it.
As with previous LEGO games, there are a bunch of bugs that come along, such as clipping issues on uneven ground, characters gaining or losing items during fetch quests, the game not registering that you have a number of minikits in a level but you do have them, etc. I found this a nuisance, but ultimately did not take away that much form the overall experience.
If you're looking for a game to share with family, especially kids, this is the game for you. It's a bonus if you like the LotR movies. If you don't like grinding and repeating levels to get everything, this isn't the game for you.