It is my personal favorite in the series, though to be fair it severely lacks in originality.
Gameplay
Now, this is somewhat original and somewhat not.
The basic jumping and the like is very, very common from the early/mid 90s, though this game made it into a limited 3D AND 2D environment. In terms of innovation, it did it's job, and was in my opinion better than BUG! for the Saturn, it didn't really have enough new to compete against Mario 64. What is original is the destroying of crates, and the destruction of all of them results in getting a gem.
I really think it's insanely fun, just REALLY, REALLY, unoriginal.
Controls
I think this game did a good job, though it wasn't as precise as per say, Mega Man, if it was it wouldn't translate well into it's limited 3D environment, so in these terms I think they mastered it.(though they somehow, must have been magically improved the controls over time)
5/5
Music/Sound
..........
This game has got to have one of my FAVORITE video game soundtracks of all time. Written by Josh Mancell and Devo man Mark Mothersbaugh. I think it's mixture of fun and delight for the early stages, along with the mysterious and tonal music for the Temple stages, and the creepy, sinister, and chilling themes of some of the cortex levels was GREAT. I don't think they could've done a better job. Though in the later games they went more upbeat, which isn't bad I do miss the very subtle and mysterious tracks this game has. The sound effects are also great, always fitting the levels.
5/5
Visuals
This is something I usually don't really talk about in games, but this games design is really one of it's strong points. It goes from the lush, and overgrown native cities to old abandoned temples from a lost people, to the evil and sinister, levels that Cortex leads over. It's attention to detail is insane, to the lush overgrown canopy outside the lost temples, to the little drops of green ooze on Cortexs' equipment. For it's time the games design was beyond awesome!
5/5
Presentation
It's map was really good, though outdated. Though the absence of an always present HUD was very welcome. The only real problem was the save feature. UGH. You have to either get a gem, or other special item, or complete the bonus stages that you can only enter once in select levels. At least in Super Mario World you could always go back to the Ghost houses.
4/5
Overall: 9/10
It is my personal favorite game in the series, though this is because I liked the kind of games it ripped off, and I thought the points in where it was original were revolutionary. In my opinion it's attempts to be more original sometimes made it less fun, and sometimes fixed things. If you're a "Crazed platformer fan" as Gamespot once put it, and you haven't played this game, try it, ASAP.