I define being a (hardcore)gamer by how much you centralize your main hobby on it. The more genres you play, the better too. 5 years ago, I wouldn't have made this stipulation, but we saw something interesting with Call of Duty: hard-core casual games. Suddenly, games that get SUPER hyped are now games that are usually catering to one type of audience, and that's the ones that don't diversify their gaming genres. I see games like GTA and CoD getting tons and tons of people playing and loving them, but the gameplay hardly ever boils down beyond kill, kill, murder, kill, all because killing is fun.
Well, killing in a game is fun, but it gets old quick. If the game doesn't expand on that quickly, my kind of gamer gets bored quickly. Enter actual gamers and hardcore gamers. If it's a video game, it's worth playing just to see how much you enjoy it. If it's got a new mechanic that's never been done before, they get excited to play it. If there's details about the game's design to be analyzed, then they will analyze it and find the best way to exploit it, or just use it as a comparison to other games with similar mechanics.
Well, killing in a game is fun, but it gets old quick. If the game doesn't expand on that quickly, my kind of gamer gets bored quickly. Enter actual gamers and hardcore gamers. If it's a video game, it's worth playing just to see how much you enjoy it. If it's got a new mechanic that's never been done before, they get excited to play it. If there's details about the game's design to be analyzed, then they will analyze it and find the best way to exploit it, or just use it as a comparison to other games with similar mechanics.