First time?
Oh I have no freakin clue...
The first time I really remember going hardcore was for Sonic 3 and knuckles (PC version) in high school. At one point, I just went "Oh it is ON!" and then managed to get all the damn emeralds. Normal and super. ....It was not easy. At all.
I might have gone more hardcore into other games before that, but I'm not quite sure...I certainly don't remember doing so....Maybe Pokemon Blue waaaaay back in grade school? Yeah, I was probably hardcore into that.....
....Ooohhh...I remember this time that I made it to the final battle against the rival, only to have ONE ice beam left on my blastoise (and all his other moves were low on PP), no revives, and no potions, with a bunch of weakened mons (I think A hitmonlee, a zapdos, and one other living one that was out of PP). And I had saved too, so I could not escape. I redid that rival battle at least 15 times, trying desperately to win, praying that my blastoise could kill the enemy with struggle, and I think one time I made it down to his damn venusaur. Finally, I threw up my hands and took the loss. Fortunately, I now had a bunch of money from facing previous elite four members, and even with half of that lost to the final boss, It was enough to buy me the supplies needed to win the second time through. Yeah, that was insane. ^_^ good childhood memories.