Harry Potter and the Half-Blood Prince

Pros

• The games environments, Hogwarts specifically looks great.
• Theres a decent enough variety of stuff to do.
• The games generous with achievements.

Cons

• But the game is over before you know it.
• The character models for the most part look alright, save their cold dead eyes.. Also Draco's head looks like it was whacked in with a shovel. Perhaps he had some kind of accident since the last movie and this is actually accurate, I don't know. But he looks like a freak.
• The voice acting is quite dreadful. If they got the actors from the movie then they didn't put any effort into it at all, if they got sound alikes they're terrible sound alikes. Hermione's voice is by far the worst offender, sounding not a bloody thing like it should.
• While there is good variety in the activities you can do, I wouldn't say all said activities were fun.
• Poor story telling.
  

Just a quickie review.
Not that the game offers a lot of write about.

It's of course based upon the upcoming movie which in turn is based upon the book, but it does a poor job of telling the story. It doesn't really tell you anything so much as it kind of mentions them in passing. It's told at a very fast pace which isn't to the games credit at all.
The story is like BAM-BAM-BAM-BAM and then suddenly it's finished.
It feels like they glossed over a lot and possibly cut out a lot of things too.
I finished it in about three hours, which probably isn't much longer then the movie actually goes for.

The game play itself is pretty much spread into three sections.

Theres dueling. All the game's combat takes place in a dueling format. Strictly one on one.
Even when theres two opponents, you defeat one and then the other will tag in.
Theres a fairly decent variety of spells at disposal. Enough that the right stick, which is used in all your spell casting endeavours - doesn't feel cluttered.
Combat is entirely too simple though. All enemies can be beaten pretty much by just knocking them to the ground and spamming your basic stun attack or later on levitating them in the air and spamming your basic stun attack. You have a defence spell that reflects incoming projectiles and you can dodge but you don't really need to use them.


Theres Quidditch.
Something I thought had the possibility to be fun but instead is an on rails, fly through the hoops kind of deal. Like everything else in the game it's entirely too simple.
Occasionally the other teams seeker will bump into you, but it proves a minor inconvenience at best. Considering that in the past they've made an entire game out of Quidditch alone I feel like they could've done more with it.

And then theres potion making, which in my opinion is probably the most fun in the game.
Sad, right? It's basically.. Cooking Mama, I guess.
You add the ingrediants they tell you to add, stir the goop until it turns to the color they want you to turn it, heat up the cauldron until the goop is the color they want it and occasionally shake up something before pouring it into the cauldron.. To turn the goop to the color they ask.
And you do that as quickly as possible, with as few mistakes as possible to maximize your score.
It isn't hard or anything, but it's still more fun then the rest of the game.

In between these activities you're free to roam Hogwarts and it's grounds and... Collect 'crests', because all GREAT games have a stupid amount of collectibles to collect.
Though I don't like collectibles in general collecting these crests is probably still more fun then the progressing through the story. Sometimes if the crests are beyond your reach you have to levitate them to you, sometimes they'll be on the opposite side of a cage in which you'll have to levitate them and break them and then levitate them again THROUGH the holes of said cage, so theres some extremely light puzzle solving there.

The game isn't actually terrible. It's fun enough while it lasts.
It just doesn't last long enough and theres too many... Quirks to be worth recommending for anything except a brief rental.