Someone who plays video games as a primary hobby. They tend to spend large amounts of time playing games, often in excess of two or three hours a day.

Hardcore gamers tend to care less about graphics then casual gamers. While some specialize in a single genre, they typically have fairly diverse taste in games, frequently playing a wide variety of games from different genres. They'll often seek out obscure and older games, based on word of mouth or positive critical reception. Hardcore gamers put good gameplay above all else, and don't mind if a good game has poor (or even nonexistent) graphics, sound, characters and plot.

The stereotypical hardcore gamer is out of shape, and has poor hygene. They spend a lot of their disposable income on video games, consoles, or PC upgrades, and a large percentage of their free time either playing video games or discussing them, online and off. They wear either black clothing, or T-shirts with geeky pop-culture references, often to video games. Their social skills may be sub-par, and they may be less likely than others their age to have many friends, a jobs and a girlfriend/boyfriend. Some of these stereotypes are negative, and they certainly don't apply to all hardcore gamers, but there's a fair amount of truth to them.

A person who devotes a large portion of their time towards gaming and gaming variations. A hardcore gamer might often attempt to optimize their playing style, often by the use of gaming gear or mods/addons; this practice is often common for casual gamers, but to some lesser extent.

"A casual gamer is someone who schedules the game around their life, while a hardcore gamer schedules their life around the game." -TotalBiscuit (a.k.a TotalHalibut; The Cynical Brit)

Apparently, what any gamer who was playing video games prior to 2006 is.

A "hardcore" gamer generally puts money down on games with actual gameplay involved. They have a somewhat excessive amount knowledge of videogames in general, but these gamers are proud enthusiasts and enjoy discussing the games they play. "Hardcore" gamers select games from specific genres and trusted publishers and have been part of the gaming industry for decades. I guess that's why they're hardcore now. Who knows.

This is contrary to the casual gamer, who has risen in prominence with the help of the Nintendo Wii and Apple iPhone. These gamers favor titles such as Wii Tennis, Wii Sports Bowling and Scrabble iPhone edition. Oftentimes, they are discouraged by the learning curve more traditional videogames require and stray away from them.

\A gamer who plays a variety of video games, based only on gameplay, not graphics, story, popularity,etc. They respect the old school, and own multiple consoles, old and new(not a fanboy.) They enjoy playing FPS's, JRPGS, Fighting games, etc. The term also applies to PC gamers.

A videogame enthusiast who does not care what system he/she is playing on, as long as the game in question is both fun (read: controls well, intrigueing and inventive gameplay, ect.) and challenging. A hardcore gamer realises that there is merit to many games on a variety of systems and often owns all of the currently available systems.

One variation on this term would be Insane hardcore gamer: A gamer who owns as many videogames as he/she can possibly get his/her hands on, often never finishing even half of what he/she owns, and also seeking out deals on famous/favourite/rare games just so that they can be added to his/her collection.

One who spends in excess of more than 4 hours in one sitting. Realises that graphics, story, fun and all the other shit are all equally important. One offsetting the other will affect the game adversely

a casual gamer minus a girlfriend, wife, job or some form of satisfying social life. They are mostly teenage boys, but some are grown men with the mentality of the average teenage boy.