Who doesn't enjoy the carnival? No one, that's who. That's why video game musicians have striven for years to distill the essence of carnival music. Instruments take on a silly quality as they bounce up and down both in pitch and rhythm. Carnival music commonly follows marching tropes at a high tempo, but don't expect me to get around to that part of it.
Assault Suit Leynos - Main Theme
The main theme of Assault Suit Leynos is certainly bouncy enough for a carnival; skip to 0:07 to hear a high-pitched glittering instrument that leaps up and down for the next 13 seconds. It may not seem like a long time when you read it, but that's 13 seconds where the music is muffled under some kind of futuristic siren.
I always have a little trouble naming instruments in FM tunes, and I'm not sure I can conclusively put a label on the lead instrument here. By my reckoning, its timbre sounds closest to an accordion, but it's way too fast for that.
In conclusion, between the bouncing siren and the speedy accordion, this tune takes on the appearance of the insane kind of performance you might see at a carnival gone wrong.
Blue's Journey - Starge Space
The cowbells here (introduced immediately) serve the same role as the siren in the previous song, but they're mixed in at a natural volume. In fact, the entire thing is soothing to hear after Leynos. Starting at 0:28, warm, fading tones take the limelight with slower, more restful passages.
But that's dashed at 1:00, where horns come in to introduce a series of musical exclamation marks for 24 seconds. While hardly abrasive, it's a surprise after the first bit, and luckily, it's befitting of a carnival's brand of showmanship. I also enjoy the laser shots that come in at 1:32.
Sonic 3D Blast (Genesis) - Spring Stadium
Well, I guess it's only responsible to include a song that's genuinely from a carnival level. When you think about it, Sonic's image is all about being a carnival ride, complete with loop-de-loops and such. I guess it's pretty convenient that Robotnik is all about building theme parks, then, and Sonic Colors is solely about trashing theme parks in progress. Eggman is really the one that maintains Sonic's image; it's just that Sonic gets to be the car that rides the roller coaster.
While I don't think I need to go over the carnival image of this tune, I do want to mention that Sonic 3D Blast remains one of my favorite Genesis soundtracks. Its production quality is a serious downgrade from Sonic 3 & Knuckles; technically speaking, it sounds like it could've been put out in 1989. However, Jun Senoue's melodies are always great here, and each theme gets plenty of variations. Careful attention is paid to each layer of the song, too, with backing melodies, basslines, and percussion that each remain interesting in their own right but work fantastic together. And be sure to throw in an act 2 variation on each tune with more thoughts on the same thematic ideas.