Honestly I don't see that being too different from, say, hunting down the secret rings in Sonic 3&K. But still, as you said, all things considered with its development, again, I'd say it's excusable.About ranking it, it gets third place in my book as far as 2D games go. Mania is first, Sonic 2 second and then CD. Don't get me wrong, 3 & Knuckles is a great game, but I feel like the level design kinda got a step down from the other games (which brings me to the "cheap traps"). It had more dynamic environments with a bigger focus on exploration but imho sometimes it puts you in immediate danger (be it pitfalls, spikes, springs), knocks you down to a lower/lesser path or away from a secret ring without any chance of backtracking or simply put, kills the flow a bit too much at times. I get that the game expects you to have good reflexes but sometimes you simply can't guess what's coming unless you've played that specific stage before. If you notice they've toned it a bit down in Sonic & Knuckles but I still prefer 2 and CD's more streamlined and fast stage design (but of course, it should be noted that even them sometimes aren't exactly perfect either...) On the other hand, Mania has hands down the perfect balance between fast and exploration-focused stages with tons of interactive and dynamic elements, they've really outdone themselves with that game!