Last time I was here, doing a short script for the first Max Payne, I mentioned that I had a stock rant about linearity in games but wasn't going to bring it up because Max Payne provides a poor example. Now, however, I'm dealing with Max Payne 2, which fits much better, so hold on while I get this bee out of my bonnet. For a long time now, linearity has been regarded as something of a gaming sin. And there are certainly reasonable arguments to be made against it. After all, interactivity is supposed to be gaming's thing. If you remove player freedom and exploration, force the player to follow explicit directions every step of the way, you might as well just be watching a movie, right?
But I think that linearity can be an advantage to a game, depending on what you're intending your game to do. Many games, particularly these days, have a strong focus on story. With current standards of digital "acting", the ability to deliver a strong narrative in a video game is higher than ever. And there are two things fundamental to storytelling that non-linear gameplay can severely hamper: pacing and character.
As to pacing: in a non-linear game, things happen when the player damn well pleases. The crisis driving the plot may have escalated to a breaking point, lives may hang in the balance, cities or worlds may be in danger, but if the player feels like it they can still go finish up some side mission where you return a lost puppy to an old lady or just go shop for new boots. The threat to the entire galaxy can just wait. In fact, a weird sort of reverse logic can set in where the more climactic things get, the more random side stuff the player wants to complete, to make sure they get it done before some point of no return sets in.
Obviously this makes any sense of urgency entirely artificial. As was pointed out on this very site, the main mission in Mass Effect was called Race Against Time, but there was nothing stopping you from ignoring it for a week while you poked around for Prothean artifacts and League of One medallions, so it hardly felt like a race by any definition. Even when this is done well, it's inevitable that the stakes won't feel as high as they ought to.
On the other hand, if something needs to be done immediately in a linear game, it needs to be done IMMEDIATELY. The game won't allow you to go do anything else. By defining what event follows after what, moment by moment, a linear game controls the pace of the story and provides a more satisfying narrative structure (as long as it's well written, of course).
But for me, the more important thing is character. Character growth is one of the defining things in story. It's not actually essential (Indiana Jones pretty much never changed, James Bond didn't learn any valuable lessons), but it generally feels like a story means more if the protagonist undergoes a change. The most interesting characters mature, they come of age, they gain courage, lose innocence, learn about themselves.
So what does this have to do with linearity? Well, think of the television series Breaking Bad. It follows an amazingly well-defined character arc for the central character of Walter White. But what if you were watching the beginning of the second season, then immediately followed it up with an episode from the beginning of season five? It wouldn't make any sense. You would be confused as to why Walt was suddenly such a cold, vicious monster, because you didn't have all the important character moments that led to that point.
In short, character growth is only possible when you have a work intended to be experienced in a very specific order. It's like comparing Prince of Persia: The Sands of Time, in which the character of the prince is slowly broken down and learns humility, to the 2008 reboot of Prince of Persia, in which he's unchanged throughout until his character makes a sharp change at the very end. The reboot had to keep the character static, because the developers had no way of knowing which order the player was going to choose to play the game in.
Maybe you think, if tight pacing and character arcs require linear structures, then the logical solution is for those things to remain in movies and books and media where authorial control is absolute. But then we wouldn't have The Last of Us or God of War or Half-Life or BioShock Infinite or any number of perfectly amazing, perfectly linear games. And we wouldn't have Max Payne 2, a story of a man slowly crossing lines, making compromises, and losing his sense of self. These games wouldn't be the same without their linear structure, nor could you just convert them into other media without losing something. So go easy on them, huh?