Currently playing Super Mario 64 for the first time ever (I picked up the DS version).

Overall, I like it. I can definitely see why a lot of people love the game. That said, it does have some odd design choices.

Turning can be really difficult. Since Mario has to actually take time to turn around, and will walk in a brief arc while turning, precision turns can be incredibly difficult, which is very frustrating on levels like Lethal Lava Land.

The adapted N64 controls also mean that it can be difficult to align Mario to any angle, as the analog stick just isn't quite smooth enough sometimes.

There are also some annoyances with the camera, as there have been in all of the 3D Mario games I've played, but I actually find that this game has one of the best cameras in the series. It freely rotates and can be set fairly easily to most angles.

The DS version has its own quirks as well. The new stars added in the DS version are really well integrated (although the new character system is a little awkward). The DS map can be very annoying, as not only does it show you where stars are, but it also makes them flash constantly, which is distracting and makes it impossible to ignore the feature. This was much better done on the Red Coins, where you have the option to see them on the map or not by talking to the Bob-omb Buddies.

That said, I really like the overall structure of the game, and I think that is what the game does best. Revisiting the worlds constantly and finding more and more in each one makes them feel better than the one-off worlds in most games. You get to really know each level, it's quirks and hidden secrets, and you enjoy hunting down a tricky star or two, or discovering something you hadn't known before. And, while the star structure can be limiting sometimes (Big Boo's Haunt, for example, where you HAVE to get the first star to unlock half the level), but for the most part, it's non-linear enough that it really rewards exploration. I tend to avoid the main star for the objective my first time into the level, and just explore to see what else I can find. Usually I'll be collecting the 100 Coins when I stumble into some little hidden alcove or something that leads to one of the later stars, and that is always a cool feeling.

It's a great little game. Not the best game, and still not as good as Super Mario World, but I would definitely rate it among the highest of the 3D Mario titles.