Circus Park from Shadow the Hedgehog: http://m.youtube.com/index?&desktop_uri=%2F#/watch?v=SUhERNt229Y
Circus Park-Night from Billy Hatcher and the Giant Egg: http://m.youtube.com/index?&desktop_uri=%2F#/watch?v=cYKMvoLgsKo
NOTE: Both of these are Gamecube games made by SEGA both with references to each other.
Please do not waltz in saying either I like none/both/some other song/spam or nag me about how impossible Circus Park-Night was because you couldn't find an obvious loophole through the rail glitch. Also, if you choose to make a post, please contribute positively to the poll (that means voting).
Edit: Moved to GC.
Current score: Shadow is winning 1-0.
This has nothing to do with Spiral Knights. Now that the Elephant in the Room has been acknowledged...
For the question itself. Both tracks sound very 'MIDI'-ish in quality, and they kind of suffer for this. Makes sense, given the time period both games were released, so I can give this a pass.
Shadow The Hedgehog's track, while notorious for its gameplay and obsession for shoehorning the 4Kids cast to utter DAMN at every turn, does sound more carnival-like than the Billy Hatcher track. I wouldn't say that this is helpful for the tone of the game, though. Immersion in the-- Oh, who am I kidding? The game was trash, and the track is just bland and forgettable.
I'll throw my vote to the Billy Hatcher track for sounding more daunting and memorable.