10 out of 10
1: That would essentially be a Sonic game with a different character sprite.
2: That's already been done before. Twice in fact.
Shadow the Hedgehog is just so enjoyable! Throughout the whole game you're fighting your way through hordes of enemies and choosing whether you're the hero or the villain. That's an AWESOME concept if I ever saw one. The game had a dark atmosphere which was perfect for Shadow's dark past, cliched though it may be. The game even has ENDLESS replay value with multiple story paths and multiple ending outcomes, which is, in my opinion, vital for a game to have; after all, what's the point of buying a game if you're never gonna play it again after you beat it? The game even plays out rather smoothly, given its unconventional Sonic gameplay; if you're looking for a challenge but want one that plays out fairly, then this game is perfect for you. Overall, I find this game is unfairly picked on for being the oddball out in the series. Shadow the Hedgehog, it was a different Sonic adventure, but man was it fun.