More than I hoped, and less...
First off, I want to be positive. The overall feel and look of this was good. The Who Wants To Be A Millionaire effect was well captured. It's not often that a quiz game genuinely feels like some effort went into the presentation.
(note: some answer spoilers ahead)
Unfortunately, you've fallen foul of the same issue that every creator of a Sonic quiz (and probably countless other subjects of flash quiz) fall to - you MUST check your facts. I'm an avid Sonic fan, and it is painfully apparent when things are wrong.
These include some tiny, pedantic points; the first question I saw asked what colour Sonic's fur is - Sonic has SPINES, not fur...
These then inevitably progress to genuine errors (one question asks how many characters you can play as in Sonic Adventure 2, which you answer as 12 - now, clearly you've counted some multiplayer characters, since you can't reach that answer any other way... but you haven't covered all of them. To my knowledge and memory at the moment, taking account of multiplayer modes, there are at least 13 Sonic, Shadow, Amy, Metal Sonic, Knuckles, Rouge, Chaos, Tikal, Eggman, Tails, a neutral chao, a dark chao, and an eggrobo. There may be a couple more...
And then there's the ambiguity that always results from these quizzes - one question asks which game did not include Metal Sonic, to which the answer was Sonic 2 - some trains of thought dictate that 'Silver Sonic', the robotic version of sonic from this game, was an early model of Metal Sonic - some form of prototype. You don't make it clear whether you mean Metal Sonic as in the overall possible scope of robot Sonics, or the famous form that Metal Sonic has become known for.
These may seem nit picking, or lame, or whatever - but when these errors continue to build up through a quiz, something is seriously wrong. And it always is with these quiz types.