I watched this again because I wanted to see if the comments I made about David Fincher in my post on Zodiac actually stood up to scrutiny.
While I may have exaggerated slightly, I think what I said holds up: The Game does have some subtext, but, for the most part, it lays everything out for the audience, theme-wise if not plot-wise.
What's interesting is that the movie's message isn't one you see very often in such an unadulterated form: Michael Douglas's character doesn't need to let people into his life or learn to treat people better or even take his job less seriously - he just needs a shock, he needs to feel what it's like to live life on the edge, or even over the edge, where life may not be worth living. It's a movie about sensations - paranoia and tension - whose message is that these sensations are an important part of life: your life may not be a roller-coaster, but it should be.
But I like the movie: it's more of a lightweight than similar what's-really-real? movies like Memento or The Matrix, but it also turns out to be more modest than those movies. It doesn't really make any grand claims about the nature of reality. It's more like a "darker" version of The Stunt Man, although it isn't as well acted. In fact, the performances might be the weakest part of the movie, which is otherwise put together with a great deal of skill. I'm not quite sure why they bothered to cast Sean Penn in a role that requires him to act normal (in all but one scene) and Michael Douglas plays it too straight - he's better when he overacts (Wall Street) or plays for comedy (Wonder Boys) or, even better, does both (Falling Down).