Hardcore is not something I aspire to *grins*
Bioshock can be borderline, upon occasions, but is not hardcore. Fighting four Spider Splicers on Hardcore with a wrench and with a pressing desire not-to-die, that can be hardcore. Mostly, no.
A game which artificially endeavors to ramp up your heartrate and encourage the pursuit of deranged scores, like Geometry Wars and it's kin, I do not consider hardcore. They try too hard.
Hardcore.. Hardcore..
Hardcore is what UT2004 would be in a 32 player server on a small map if anyone really cared about the objectives.
Hardcore..
True hardcore is something I've rarely found.
Ah - Neocron and Planetside achieved true hardcore. It wasn't the pace of gameplay, which was merely respectable in both games, it was the scale of it, and the weight of the objectives. No-one wants to die in an MMO, objectives seem more epic when 200 people are fighting for them.
A gang war on the streets of PepperPark in Neocron, a 200 man 6 hour battle across the northeastern quarter of Ishundar in Planetside...
That was hardcore. When it's raining artillery and you know every shot was fired by a real player, when bullets are hammering your cover and you're getting reports on teamspeak that a guy on a higher tier channel got reports from the commanders on highest tier that six New Conglomerate tanks are en route with a squadron of Reavers.. Hardcore.
Merely running very fast firing a rocket launcher or adding up your score muliplier is not hardcore. It wishes it was

To be hardcore, you need to care about success, and for more of a reason than getting a higher score than your little brother, I think.
Yum. Hardcore.