I don't have the same thought into what a casual and hardcore game is. To me, a hardcore game is one that is difficult basically to the point of pulling out your hair and screaming in agony. Games like Ikaruga, Panzer Dragoon Orta, Contra 4, Super Monkey Ball, Guitar Hero, Guilty Gear and Ninja Gaiden fit this bill.
A casual game is just easier to play through. I have no restrictions past that. If I don't need to completely concentrate my energies and basically memorize enemy positions and practice for weeks to get even remotely good at the game then it's casual.
Gaming was on the whole much more hardcore back in the day, as most games hold your hand and pat you on the back the entire experience nowadays, instead of the pimp slap games like Super Mario: The Lost Levels, Ghosts N Goblins, TMNT, Castlevania, Mega Man and many others gave you in the old days. In many games, your reward for not fucking up once was your ability to simply continue on. It was required for you to become good. Now imagine something like Bioshock nowadays instead of placing you in a Vita Chamber everytime you die simply gave you 5 lives and 3 continues, with the wonderfully hard position of having to start completely over if you can't beat it. That's what hardcore is.
Tag: Became a freaking mod and a complete douche, coincidentally, at the same time.
