I feel this "Review" isn't going to be the review you would expect. I feel I need to clarify right off the bat. I'm not a Mario fan (never have been); platforming is fun, but Mario games in specific are not my thing. I got my Nintendo 64 Christmas day 1998, and this game came bundled with it. I remember the shock of going from Super Mario World to this, and I couldn't fathom not using the D-pad; using the analog stick didn't make sense to me.
Looking at the game today, it didn't age well in the slightest, but for it being the infancy of 3D gaming, lots of jank is to be expected as they iron out the bugs. For what it's worth, though, in my opinion, the early stages are a lot of fun; the later stages are a rage-inducing mess, and the rough camera work doesn't help. The last time I played this game, I did finish it, but not legitimately; I didn't get the 70 stars, but did the backwards long jump glitch to bypass the endless staircase. Overall, the game is fun, and I slightly recommend it, but if it's your first time playing, for your own sanity, don't try to 100% it; play the early levels and see how you feel about progressing through the more BS levels.