3&K takes over so much of this game's conversation I honestly forgot the two halves were playable separately - hell, that's how childhood me first played them! Even though I had the S&K collection, nobody in the family was smart enough to get past The Barrel - so the bits of the back half I saw were from booting &Knuckles directly. Toddler me didn't even realize 3&K was the two games combined until later - I just assumed it was a bonus version of 3 with Knuckles playable.

And honestly? S&K alone is a vibe. Something about it has this unspoken edge when treated as an isolated continuity - hard levels right out the gate, no tails to morally support sonic, mostly roboticized or harsh environments, and no save feature as a safety net. S&K also feels like a realization of Sonic 1's design philosophy, which focused most heavily on platforming supported by speed instead of the other way around. You get that scheme here but with infinitely more meaningful level design and much better pacing.

Main flaw is that (A) you're missing all the amazing content from 3 and that grander 'adventure' feeling, and (B) S&K has a pretty rough zone quality ratio. Mushroom Hill's my favorite Classic Sonic hill stage, and Flying Battery is raw, but then Sandopolis and Lava Reef are mid, followed by cool-but-short Sky Sanctuary and the overly-tedious Death Egg.

Cartridge shape is a bitch to organize on a shelf and I'm not stacking enough paper to buy a box for my copy rn. I got other financial priorities and shit