Hm, the day it came out? Unlikey i ever did that. I mean you had to hear about it first, which means somebody had to have it first? Also i lived in a a village, which means the shop likely had to order it, if it wasn't a big title. Usually games "found their way" to me months or years after release.
Possible that i read something in a magazine and went out and through luck got it fast.
Well, i remember having my brother in law get me "Mortal Kombat IV", when i wasn't 18. That was planned and expensive i remember. Might be nearly day 1.
Also i got myself Max Payne 2 and Half Life 2 full price at launch. But that was years later.