These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Best Level Ever: Consensus seems to be Speed Highway, the fastest-paced Sonic level in the game. Sega appears to be part of the consensus, as they practically brought it back in Sonic Adventure 2 (under the name "Radical Highway") and chose it as the representative stage of this game in Sonic Generations.
Broken Base: The alternate gameplay, which is either a superior or inferior way of handling multiple playable characters compared to the previous Sonic 3 & Knuckles. There's also a camp who believes that the alternate gameplay in this game is better handled than in the succeeding games.
E-102 Gamma is also among the first and few supporting playable cast since the 3D era that rarely brings up bile, despite him being in only two games.
Esoteric Happy Ending: At the end of Super Sonic's story in SA1, Tails says "all's well that ends well," even though all of Station Square had just been demolished and flooded by Perfect Chaos's rampage, and unless the buildings were conveniently empty, at least half of the population had to have been killed, or at the very least injured.
And in some way, Eggman becomes a Karma Houdini after having done the wrong to the city and its population and getting away scot-free, although getting the Egg Carrier II destroyed by Perfect Chaos arguably counts as karma.
Not to mention some glitches in the game that allow characters to enter usually inaccessable areas or play around with unused content in the game (there is a glitch method for nearly every character to get into Emerald Coast for example). Granted a lot of them have the potential of screwing up gameplay or save data.
Possibly not a bug, but if you use the Light Speed Attack when fighting Chaos 6 as Sonic, it'll do double the damage and you can beat the boss in under a minute.
It also works if you have the Fighting Gloves and use the Maximum Heat Knuckles Attack when playing as Knuckles.
Harsher in Hindsight: In Super Sonic's story, Perfect Chaos floods Station Square, leaving the city a destroyed mess, and no doubt drowning many people. Fast forward to 2004, and we have the Indain Ocean tsunami. One year later, and we have Hurricane Katrina completely flooding New Orleans and killing over 1800 people. Flash further forward, and you have the tsunami and earthquakes in Sendai, Japan. Then, a year after that, Hurricane Sandy in 2012 caused another disaster.
The intro depicts Perfect Chaos crashing through a skyscraper, and then 9/11 happened almost exactly two years after the game's release,
Also the fact that after you finish E-102 Gamma's storyline, he dies shortly afterward. This becomes worse when you realize that his English voice actor died shortly after this game was finished, and Sonic Adventure 2 had just been released.
It's the Same, Now It Sucks: Sonic Adventure reviewed quite positively during its initial release on the Dreamcast, as did its sequel, and the Updated Re Release of said sequel for the Gamecube. Sega went ahead and similarly re-released Sonic Adventure as Sonic Adventure DX. Despite being a faithful port that significantly touched up the graphics, fixed a lot of the glitches, and added a whole new gameplay mode and bonus character, DX received middling-to-negative reviews from most gaming publications, often times scoring several points lower than the reviews of the Dreamcast version of the game by the same publication.
"You're gonna crash, ah!" note An infamous line delivered by Sonic early in the game when he sees Tails' plane crash. The utterly wooden delivery of the line, combined with Sonic's ridiculous facial expression, has made it a classic meme.
"Oh no", delivered in monotone by Sonic or Knuckles.
GET A LOAD OF THIS!note A very popular, over the top line Eggman spouts repeatedly during both the Egg Viper fight and Egg Walker fight.
Moral Event Horizon: The Echidnas trampling and killing the poor chao standing in their way just to get to the Chaos Emeralds and the Master Emerald. They didn't have qualms about taking down Tikal either (she wasn't killed though); even her FATHER Pachacamac didn't care, just as long as they seized the emeralds. This wasn't a very good idea.
If you exploit a glitch that allows Knuckles to reach Sky Deck through the Egg Carrier's swimming pool, you'll enter his flackback with Tikal as normal, but there will be no dialog whatsoever. Even when you reach the area where the emerald shrine is on fire and Tikal and the chao are laying on the ground, no cutscene plays, making it seem as though they're all dead. The kicker? You're stuck here forever. If you quit the game and return to Knuckles' adventure, he'll still be there with nothing to do but watch the shrine burn endlessly. The only way to fix it is to start a completely new file.
Porting Disaster: The 2004 Windows port is marred with problems. It suffers from grainy-lookings visuals, poorly re-sized HUD/UI elements, bad horizontal stretching, the game being prune to crashing when switching out to another window in fullscreen, keyboard controls can't be reconfigured, poor implementation of mouse controls (thankfully they're optional), and poor optimization (at most it will run at 30 FPS). The game was re-released in 2010 on Steam, based on the Xbox 360 port but introduced new problems such as the game's launcher not saving your settings, game running a locked resolution, poor frame-rate despite the Xbox 360 version being capable of running the game at 60 FPS, and the game is presented in a pillar-boxed 4:3 aspect-ratio. A patch was released in 2014 that fixes the issues with the game's launcher not saving settings, fixed the controls (keys are rebindable), better support for higher resolutions, V-Sync, and FXAA. However the issue with the game's frame-rate remains unaddressed, it still runs in a pillar-boxed display, and despite supporting controllers, the triggers and D-Pad of an Xbox 360 controller does not work at all despite being based on the Xbox 360 version.
Polished Port: The GameCube release of Sonic Adventure DX: Director's Cut received a graphical overhaul, new bonus missions, twelve unlockable Game Gear games, and the ability to play as Metal Sonic.
The Scrappy: Big the Cat for a great many people, and not just because of his levels.
Base Breaker: Of course he has garnered a plausible fanbase over the years to balance it, especially following his cameos in the latter title below.
Scrappy Mechanic: While all of the 3D games have bits of this, SA1 has one of the most loathed in the form of Big the Cat's fishing stages. If you jiggle the control stick even slightly the wrong way, you don't get the fish on the hook, you move the line the wrong way, and you have to reel it in exactly right or it will just magically get off the hook, at minimum stress, when it's right next to you.
Hunting for Emerald shards is also well-hated.
Seinfeld Is Unfunny: Despite being one of the flagship games of the Sega Dreamcast and a critical darling when it first came out, many note that this game does not stack up well to its much better-designed successors in hindsight, which probably contributes to its Deader Than Disco status mentioned above.
As noted above in Franchise Original Sin, this game also introduced a lot of things that would become cliches in the series like Robotnik getting upstaged or the Chaos Emeralds being used as an eleventh hour power-up. At the time this was all fairly revolutionary for the games (Robotnik had never been eclipsed as a threat by another villain) at the time, but they got overused so much that it seems trite.
Sweet Dreams Fuel: This is the game that introduced the Chao: adorable little virtual pets that you can feed and give small animals to play with.
That One Side Quest: Try the Ski Slope Snowboarding missions (53 and 54) in the DX version's mission mode and you'll find it very hard to not go crazy trying to beat them. To add insult to injury, you risk running into a bug that crashes the game if you save mission 53 as your last one.
That One Level: Hot Shelter as Amy. It's not especially difficult, but it's like the level equivalent of Goddamned Bats: very long and full of annoying mechanics like doors you have to open by twizzling the analogue stick (which, if you have the PC version of SADX, means mashing the arrow keys in the correct order) and key hunts. Meanwhile the robot Zero is chasing you and putting you under constant pressure the whole time. No wonder the developers gave it an A-Rank time of 6 minutes 30 seconds...
Most of this is because Sonic generally visits the majority of any given stage, but Sonic never goes to Hot Shelter, so Amy gets the job of showing the level off instead. Amy's playstyle deals with slower gameplay than Sonic's does.
Some of Sonic's A-Rank levels are horrendous, and the first level (Emerald Coast) is a prime example. It's a fairly straightforward level to run through on the C and B levels (finish the level and finish with 50 rings, respectively). For the A-Rank, though, you have only two minutes, forcing one to spindash almost nonstop through the entire level while taking all of the stage's normal shortcuts (as in the ones the developers wanted you to take, not Game Breaker shortcuts found by speedrunners). It gets worse with levels like Red Mountain and Lost World, to name a few.
Big's A missions. Catch a 2000g fish and then catch Froggy. It doesn't sound hard, but there's pretty much only one fish in each level that has this, and the fish you catch respawn. Doesn't help that the fishing mechanics can be buggy (see Scrappy Mechanic).