What is a video game genre?

Here's a weird question you may not have considered before: why are game genres different from film or literary genres?

You'll notice that video game genres tend to be defined by how you play them. You have first-person shooters, roleplaying games, real-time strategy, arcade games, and other similar classifications. These all address either the control scheme or the core mechanics of the game - FPS describes a game where you shoot people from a certain camera angle, RPG describes a game where you develop the personality and characteristics and story of one or more characters, RTS describes a game where you control many units in a large-scale battle from a top-down perspective, etc. 

What's important to notice is that these designations ignore the content and mood of the story - first-person shooters are described as FPS games first, regardless of whether they're sci-fi, historical fiction, horror, funny or serious, oppressive or action-packed.

On the other hand, literature and film tends to be classified by the type of story being told: a romance is about people who fall in love, horror is scary and often doesn't end well, comedies make you laugh, and so on. You can often get a sense of where the story will go based on the genre - if you saw identical synopses but with different genres assigned to them, you can assume different things about the narrative with some degree of safety.

Just to illustrate the point, if books were classified the same way as video games, when someone looks at the cover of Frankenstein and asks what kind of book it is, you might reply "it's an English Victorian novel" instead of "it's Gothic science fiction", describing the style rather than the content. Doesn't that seem kind of weird?

I think the reason is twofold, but the reasons are very strongly related. I think that games depend more on how you feel about the mechanics than do movies or books. You might stop reading a book because you don't like the author's style, but I bet you're more likely to quit or dismiss a game with a control system you don't like. As an example, if you recommended to me a console shooter, I would probably never play it because I have a (very strong) preference for mouse and keyboard controls. But with books or movies, if you recommend a historical drama when I generally prefer science fiction, I won't simply dismiss it because it's outside my usual comfort zone.

The second, very related reason is investment. If I go to the theatre and see a movie that I end up hating, it cost me two hours and ten bucks. However, if I buy a new game and it turns out that I hate the controls or mechanics, that's a loss of $60 and quite possibly five or ten or more hours. I personally find it much harder to enjoy the story of a video game if I'm annoyed or frustrated by how it plays. I hear Halo's story is quite enjoyable, and I do love a good science fiction story, but I may never play through it because I don't like aiming with thumbsticks. *

To summarize that in one sentence: Half-Life 2 (for example) is an FPS first and a dystopian sci-fi second is because if you can't get past the FPS you'll never experience the sci-fi dystopia.

That said, the weird thing, and where this whole article breaks down a bit, is that some game genres fit in better with the literary ones. For example, when talking about Amnesia: The Dark Descent, it tends to be described first and foremost as a horror game, rather than a first person adventure/puzzle game. It might be because horror games often have a very strong atmosphere, so strong that it overrides controls in terms of description priority.

But aside from those exceptions, I think it fits to say that game genres are described the way they are is because of the importance of the player's comfort with the control scheme and mechanics. As I said above, it seems to me that it's much easier to enjoy a movie of a genre you don't like than it is to enjoy a game with controls you hate.

But what do you think? Is there anything I missed? How do you feel about game genres being assigned as they are, fitting Call of Duty and Bioshock on the same shelf when their narratives and settings are so vastly different?

* I know Halo 1 and 2 are available on PC, but then I'd have to start the series and be unable to finish it, which may in fact be worse than not playing it at all.