There are no casual games, or casual gamers. There, that's all you really need to know. You can skip the rest of this post.
Or not.
Hardcore gamers (or "core" gamers as Reggie Fils-Aime likes to call everyone who still obsesses over the 124th game to star Mario) often deride "casual" games. Games like Wii Sports, Wii Fit, Farmville, et. al. are constantly derided as being fit only for casual gamers. Casual gamers being those people who don't actually care what games are being released this month or what Roger Ebert thinks about video game or who provides the voice of Miranda in ME2. (Not that a casual gamer knows what ME2 stands for. He would think it's a typo of Einstein's Theory of Relativity. If he even cares.)
But, games in and of themselves are not hardcore or casual, rather, it is one's approach to the game. I spent a couple months playing Farmville earlier this year and I can personally attest there are hardcore Farmville players. You don't need to try this yourself, just visit one of the many Farmville help sites or wikis and see how they've broken down every resource by the amount of coins you earn per hour per square of land and it becomes obvious there are some very hardcore players harvesting ghost chili and collect eggs. If you do play Farmville, you can tell the hardcore players right away. They are the ones with their avatar penned in and every square inch of their farm occupied by golden chickens and multiple crops planted in various states of ripeness. They probably also have two or more Facebook accounts so they can run multiple farms and share stuff with themselves.
The reverse is also true. Just because Halo is considered hardcore doesn't mean there aren't Halo players who slogged through the single player on Easy and never touched multiplayer or only play it when there's a Halo party at their friend's house. Even those of use who consider ourselves hardcore don't approach every game that way. Of course, we would consider any game we play casually a "casual" game, discounting there may be someone out there who knows every trick to getting a high score in "Soccer Heading."
Further, even the distinction between hardcore and casual gamers is a false dichotomy. A person who rarely plays video games may latch on to a specific game--say, Animal Crossing--and become completely "hardcore" about the game, learning every trick in the book. Another person could become hooked on Wii Fit, but never play anything else. Etc. The only real distinction is between people who play games and those who do not--and the number of people who do not play games is steadily shrinking.
In this new world of people who game, it behooves us to stop trying to create artificial divisions in our ranks. No, not every person who plays wants to go to PAX or Comic Con (or even cares what they are), but we are all gamers. Or, as Kevin Butler says at about the 4:20 mark of this video:
http://www.youtube.com/watch?v=mGZbJlpsohc
"Every gamer is a true gamer."