Like any high school reunion, Sonic 4 Episodes 1 and 2 are varying degrees of disappointing. Though good for its time, Adventure just doesn't hold up as well today.
And I'm not even addressing the painfully bland hub-world content and miscellaneous fluff that constitutes the bulk of the game's overall experience, nor am I mentioning the (very) poorly aged graphics. Unfortunately, Amy's plodding play style and Big's fishing (yes) really, really weigh the experience down, especially when you consider how rough around the edges the other four characters' gameplay styles are. Gamma's linear, third-person shooter segments are inoffensive, though not terribly engaging. Heck, even Knuckles' treasure-hunting escapades are kind of entertaining.
And it's a shame, because the Sonic and Tails portions of Adventure are pretty solid! Sure, the level design is janky and at odds with the player's speed, but overall, the Sonic and Tails stories offer up stretches of good fun. While a bold and respectfully competent move into three dimensions, Sonic's first true 3D outing ('but what about Sonic 3D Blast?' the peanut gallery inquired) remains one of his least entertaining titles.