LA Noire
In short, good game. Maybe even great, though I can't really be sure until I've finished it. Hard, though; the game makes a big deal about reading the expressions of the people you interview to tell when they're lying. The instruction manual gives some tips, and recommends you "trust your gut", reminding you that you have years of experience at reading people's expressions to tell when they're lying while also forgetting to mention that they've done studies and shown pretty conclusively that human beings are terrible at spotting a lie based on facial expressions. But that's not the tricky part- these are actors, they've been told to "act like you're lying" when their characters lie, so it's pretty easy to spot. No, the hard part is knowing what piece of evidence you should present to them to contradict the lie they're telling... in some cases, it's obvious, but often times it feels mostly like a guessing game.
Also, important note: this is not a game about solving mysteries. This is a game about solving crimes. It might seem like the same thing, but LA Noire drives the distinction between them home. It's less about attention to detail and lateral thinking to put together clues, and more about following a breadcrumb trail of clues to an eventual arrest. And boy howdy if there aren't times where the game asks you to put away a suspect that you, in real life, are not convinced is actually guilty... though in fairness to the game's developing storyline, I feel like this is mostly on purpose.
There are also some technical issues... gunfights are occasionally trickier than they need to be due to an occasionally frustrating camera and cover system, but for the most part these sequences are optional and even when they're not, the game gives you the (sissy) option of skipping past them altogether. And imagine a game with "Grand Theft Auto 4"'s driving mechanics that *penalizes* you for running over idiot pedestrians...
Still, the focus is on the investigations, interrogations, and the story. And the game gets these mostly right. Main character Cole Phelps is certainly no Sherlock Holmes, but as a procedural crime drama the game comes through in spades. From searching the crime scene for clues (and the special thrill you get from finding the ones that aren't clearly labeled) to getting the coroner's report at the morgue to grilling a suspect in the interrogation room while your angry lieutenant scowls at you from behind the two-way mirror... all the elements are there. The atmosphere may not be quite as rich as "Red Dead Redemption", but that honestly could just be a preference for Westerns rather than detective stories, and for the most part the immersion is almost perfect. Sure, it still has the issue of every pedestrian in Los Angeles having one of six possible things to say as you pass by them on the street, but overall the script is top notch.
In summary, this is a game people will be talking about for a long time, and it's probably a shoe-in for "Game of the Year" awards from all over the industry, so you should probably play it. It's not perfect, but it's good enough that you'll hardly notice.