Honestly, SA2 is my least favorite Sonic game. In SA1/SADX, you were given stages which give you the option to explore, while giving you the option to just straight complete it, while staying fun. Explore or go fast as Sonic, have a fun race with Sonic as Tails, and explore or find some emerald pieces as your favorite echidna boy, Knuckles. You also have Gamma, which is good for people who like both shooting things and Sonic. You also have Big, which is ok if you aren't doing the missions, but he should just be included in a seperate SEGA game. And then Amy, who is also ok, albeit not the best character. And then, you have HUB worlds. You can talk to NPCs, you can explore, you can find glitches, unused stuff, etc.
But then, you play SA2. Unfun linear stages, nerfed SA1 gameplay, less fun Gamma gameplay, nerfed radar, and too big Knuckles stages.
SA2 is my least favorite game because it didn't give me the Fast 3D Sonic I wanted. SA1/SADX offered me that well enough, while SA2 slowed Sonic down. At least it removed Amy and Big. The plot for both game was ok, but SA1/SADX's one was more memorable for me, along with its quotes (ex. Watch out, you're gonna crash, AAAAAAAAAAAAAAAAH!!!!!!!!!!!!!!!!!!). They both had good voice acting in my opinion. SA1/SADX also has those goofy facial expressions, lol.
Also, I wasn't really into discovering SA2 that much.