I would also like to voice my $0.0002 cents of personal opinon...
I LIKE MARIO 64 !!!!! Its a great game !!!!
Yes, on each world (level), you can get star by collecting coin, but that's not all, you have some races, puzzles, and beating bosses, tasks to do.... etc.
Its been yrs, but I think you can finish the game... beat the last bowser after 70 stars.... and there are like 110+ stars....
If my memory serves right, I think I have got all the stars (maybe left one 1 or 2).... that's it..... (but I did visit gamefaqs.com....) call me a cheater, but some of the places that they hide the stars are quite unique !!...

I think this really is a game where adults and kids can enjoy, and also the player, and the ones watching can also enjoy...
(of course, like all puzzle games... once you beat the game like 100 times, it'll get old...)
but the design of each world.... I really think they have put some serious thoughts about it !!!.... like those water levels...
the swimming.... the view angles... the jumps....
I really think this game is TRULY UNIQUE.....
and I think Mario 64, and Mario Cart 64 (multi player mode), these 2 games alone is already worth the N64 Console....