This game is a lot of fun, and personally I think a lot of the dislike is unwarranted (but has a lot to do with the fact that the game shows its true promise far past the first playthrough). I 100% believe that if this game was not explicitly titled "Sonic 4", the game would be more appreciated. (To be fair, I rightfully will agree this isn't a "successor" to the classic Sonic series, though. It's better treated as its own separate thing.)

This game has:

- Actual fasts (way faster than Sonic the Hedgehog 4 - Episode II, where you're forced to use Tails a lot)
- A mere 4 main zones, making it short and sweet instead of too long like Sonic 3 & Knuckles is.
- No glitches (at time of writing this), making it automatically better than 90% of Sonic games, including Sonic Mania (I must disclaimer by mentioning the possible crash right after you obtain all the emeralds tho, only a thing on PC for some reason)
- The most fluid Special Stage in all of Sonic [Special Stage 5] (seriously, check out a run and marvel at the sexy freefloating for much of the level)
- Speaking of Special Stages, Sonic 1-style stages that put you more in control - with time limits!
- A Labyrinth boss that actually is fun and challenging
- Shortcuts that make you wonder why you ever did the puzzle room in Lost Labyrinth 2
- A final boss that has a trick that makes you wonder why you ever struggled with Phase 2
- A simplistic, fairly lenient, and fun scoring system that gets even better when you turn Super
- An actually fun casino level

...and much, much more!

By all means, get it on sale, though, it's been super low priced many times already.