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 gamer
s, 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)
Jim plays World of Warcraft
and devotes the majority of his time to his raiding guild, including altering his real life schedule to suit his guild's needs. Hence, he is, to some extent, a hardcore gamer.