Adventure 1 is still the one I replay the most often and not get tired of it. Even with the other characters, it just seeps with anarchic imagination, how they use the existing levels is almost kind of genius, and Sonic’s feel is top notch and in a story you can replay from start to finish without working through the other stuff.
BetterSADX really lets it shine.

Generations’s level design on both sides of the coin is really fun where I still discover new things about them each time I go back, the side missions are a nice bit of extra content using them, as is the Skill Shop which no other boost game has brought back since. Bosses are very enjoyable for the most part and the modding community makes it a great PC hotspot. But the nothing story and punch of both Planet Wisps followed by Time Eater does sadly drag the endgame down.

Frontiers has so much of what I wanted to see in the Modern series tonally and stylistically. It has a commendably varied soundtrack and I can’t stop thinking about the Super Sonic battles. Cyberspace I think pales to Generations levels and even their side missions, but they’re quick, and serve well as a break from open exploration. It feels like the first 3D Sonic game with a soul since 2009 which is impressive for how basic the biomes are but I wish it had more consistent terrain physics so you could take advantage of the speed tech more consistently. Final boss is better than Time Eater I WILL carry that.

Colors is fairly consistent and quick. It just works (at least the Wii original). It’s easy to enjoy the entire run without much hassle but it doesn’t have the highs of other games with more problematic design decisions.

Adventure 2 has higher highs than some above, but far lower lows. I still appreciate the more tech approach of the speed stages, but some mecha and Treasure Hunting took a massive hit; I don’t like the car levels at all. I will say; I think it does the best job contextualizing all the different stages in the plot, plus there’s the Chao Garden.

Unleashed’s day stages, music and aesthetic are an incredible series high but there’s just so much Werehog and mandatory medal padding; which kills the pace and doesn’t give you the more seamless freedom to work around the collecting like in Frontiers. I admire the audacity behind Eggmanland.

I like Heroes’s gameplay loop and art design (minus the plastic characters), not enough to finish the game four times, and the casino stages + Rail Canyon are pretty hard lows. Egg Fleet is a personal favorite 3D Sonic level though. Also has the WORST bosses in the entire 3D series aside from Egg Emperor sorry not sorry.

I adore Black Knight's tone, presentation, soundtrack and style, especially around the ending, though the level design itself is very bland, and most of the bosses blow because of the wacky waggling. It's mercifully short for separating the fat though.

I commend Lost World’s variety and parkcour implementation (when the game actually lets you, which isn’t often) in a core look, but its measured design is antithetical to what I personally adore about Sonic, especially with the story, and most stages do not trust you to keep a pace up. The Zelda DLC is cute.

Forces is a hollow shell and a complete flatline. Classic Sonic is basically broken and the other two playstyles function but just make me want to play Generations again; feels like a half-hearted budget title made for the bargain bin just based on adopting various surface level claims about the series. Infinite’s theme is gas but you can’t hear it in game for more than a few seconds.

Shadow’s gameplay can occasionally be fun in a guilty pleasure kind of way in a couple levels, shooting actually flows fairly seamlessly with your movement, but the tasks are overly strict and tedious, while The Doom is my least favorite level in any 3D Sonic. It’s so bad. . . . . .

If 06 was JUST the Sonic levels with some more polish it might’ve been higher but it has everything else dangling its neck. Screw the hub worlds. Godspeed to ChaosX for P-06 but that doesn’t automatically make vanilla better.

Has the worst feeling Sonic out of all of them at the start, has the most esoteric mission structure and is far and away the most stop/start game out of all of these, which I think is horribly antithetical to Sonic. Also the worst homing attack and worst grinding mechanics.