I finished the game with all 120 stars and still haven't understood how the cannon is used...
You're kidding right?
There were sometimes that you couldn't see where you jump!
Yeah that was kind annoying,but you could adjust the camera if you were really desperate.
The game kind of sucked compared to other 3d adventures such as Crash and Zelda.
Crash sucked compared to Mario64.I can't even think of comparing Crash to Mario.The Zelda games were supposed to be rpg not platform ,and they were the best N64 games ,so you can't say Mario sucked because it was inferior of them.And in any case Mario was released with the console itself,but it remained in the top 10 platform games of its time for years.All the other platform games of N64 (banjo-kazooie,donkey kong etc...) just copied it.
p.s.(If you want to really know what is an adventure game look
here.The games you mention cannot even remotely be called adventure.)
In the real N64 you can't save anywhere
I think you mean:you can't save everywhere.
I know ,I've got a N64 myself,but that's not a disadvantage.The game would be too easy if you used save states.It was easy even without them.