Sonic the Hedgehog 4 Episode: II

[Mutsukki]

I kinda felt the same way about modern Sonic, I liked the exploring in the Adventure series. But the level design in Generations (and Colors. Actually, maybe Colors' level design is better) is indeed very clever, even if you can't catch all of it at once, you can go back and see all the details and alternative paths that are there (Especially if you want to get every Red Coin)