My first Fallout experience was with Fallout 1's demo. If I recall correctly, it took place in one area of Junktown.
I was not yet fluent in English so some dialogue bits were a bit difficult to make out of. (Though playing Daggerfall while learning English did help a lot on this part)
So I spent more time killing off everyone in the area, including the poor brahmin, than doing the couple quests.
Like Derragorn, I was hooked when I found the minigun and started mauling everyone to death. My older brother than bought the game on its release, along with Fallout 2 when it got released.
Ironically, I didn't go far in Fallout 1 because, as mentioned above, there were a lot of dialogue bits that I didn't understand or that I misunderstood. So my favourite thing to do was to load my brother's save at the end of the game with the most powerful equipment, then cause rampage in every town.