Knuckles' Chaotix is a precisely designed delight; the challenge being to make the terrain work for you.
I know many who dislike it, and I can understand why. In some cases, they don't have the patience to play it properly and, in others, they simply prefer something more straightforward. That's not entirely me throwing shade. Knuckles' Chaotix plays completely unlike any other game in the series, with the exception being Sonic CD (it, too, being focused on exploration). It's interesting to me that, even when someone carefully explains the design of Knuckles' Chaotix, people still insist that it's bad. It isn't. If you want to go left to right to bop enemies, then yeah, maybe? It's not made for that. It's not what you're supposed to do.
It's made for exploration, you see, quite unlike any other Sonic (CD aside). The overall objective of the game is to collect all the "Choas Rings" by collecting enough rings during the regular levels to afford yourself enough time to clear the special stage at the end. This isn't mandatory; you can also just run to the end of the level, ignoring the rings and the special stages. If you play this way, you're missing the point. It's no wonder people who do find the game and it's level design boring and frustrating - they should be striving to collect as many rings as possible, and to avoid the (admittedly too few) enemies to avoid losing them. The levels are designed, mostly, in such a way as to keep your speed up and lay out a usually obvious path of rings to collect; besides Amazing Arena, playing this way works. That's really the only level that doesn't really fit Chaotix's design - you have to find a switch to turn the power on before the game will let you complete the level, and many of the stages in that zone are labyrinthian and unfun. Still, the rest of the levels work well with the mechanics, and are beatable on repeated playthroughs much quicker, showing that there actually is decent level design here, contrary to the belief of most.
The game is somewhat hamstrung by it's title, in my opinion, as well. Though playing as Knuckles is in no way bad, if I were the designers, I'd have made Vector the main character of the game. His abilities - double jumping and being able to climb walls - compliment the mechanics perfectly. He is not Charmy, whose ability to fly infinitely pretty much makes the mechanics pointless and the level design even less focused, and he's not the awful Heavy and Bomb characters, who should be removed from the game entirely. They can keep the dumb claw minigame in, just don't make the player be literally weighed down by losers if they're not good at it. Anyway, Vector's ability to double jump can be used sideways to get an instant boost in speed, and can mitigate bad jumps or those situations where the rubberband is bouncing your pair of characters essentially in place.
The excellent special stages are the cherry on top - for many, the best part of the game. They are 3D blue sphere collect-em-ups, but unlike the similar sounding Sonic 3 special stages, these take place in a polygonal tube that your character can move around in any direction in, in order to avoid falling off the stage or getting hit by spikes and losing rings (and thus, time). They take some getting used to after 30 years of fully 3D games, but once you understand how you move from side to side, they're a lot of fun to try to complete, especially if you played well in the 2D stage and gave yourself plenty of time.
Knuckles' Chaotix is a game I used to think was awful, coming from Sonic 1, 2, 3, and even CD. I thought it was a point-missing, confusing mess, drastically divergent from the mainline series. After a while, I actually tried to collect all the Chaos Rings by getting as many rings during the levels as possible and realized, it was, in fact, delightful. A lot of the common complaints about Knuckles' Chaotix are instantly resolved by learning how to play it correctly and by understanding its mechanics, its intended goals, and how to achieve them. The effect on the game is - without a word of hyperbole - transformative. It becomes something utterly unique - not just as a Sonic game, but among games, period. It is a beautiful snowflake. I'm so glad that I took the time to learn how to play and am now hugely appreciative of it. The speedy, sometimes awkward, wonderful design that only comes to the fore when you care to put the effort in.
I adore it. It's a sprawling, revelatory delight.
