It was a great game, and a very good pack-in choice due to the broad appeal of platformers. Another reason I believe is...
Green Hill Zone! It's one of my favourite levels in a game ever, and the only Sonic level that surpasses it is Palmtree Panic, only because it's like Green Hill times ten.
When people first played Sonic (many of who had just upgraded from the NES) they saw the detailed and beautifully coloured background with the stylish checkerboard ground, they heard the rich 16-bit music, and they felt satisfied about their purchase. (too bad Marble Zone came right after)
I LOVE ICELAND!








