Also, I never really mentioned anything about the Lost World's story and writing.
In terms of the story/plot, it's not that deep, but in terms of writing, and character interactions, it's actually got quite a bit of depth. And if you like Sonic, Tails, or Eggman, you're in for some fanservice, as they not only do some very funny things with their relationships, but also deeper and more poignant things. The writing just has a lot of emotional drive. I suppose that'd be the best way to put it. There's even a bit of character development for the 3 of them (heck, EVEN Orbot has some character development).
Also, Sonic's comic timing in this game is literally perfect. The characters in general all have amazing use of body language.
And Tails is such a sarcastic and witty bastard at times, and I love him for it. But he still has a childlike innocence, which is highlighted in some key scenes. Not to mention that he was one huge Crowning Moment of Awesome near the end.
And Eggman is Eggman, with even more excellent lines, and yet another flawless performance from Mike Pollock. In fact, I think Roger Craig Smith and Kate Higgins also had flawless performances. Remember how I said not too long ago that I wasn't sure if Roger could provide a good performance for Sonic if the tone of a scene was more serious? Well, he completely erased my worries there in a bunch of scenes. He really just has perfect delivery here, whether it's a funny scene or a serious scene.
As for the Deadly Six, as individuals, they are not too interesting, but I do love Zazz (the pink maniac), Zor (the emo guy), and Zeena (the girl). Zavok (the muscular red guy) is also growing on me, and his voice is deliciously evil.
As a collective group though, they are awesome, and I'd love to see them again. There was some potential for backstory with them, but we don't get much. That's the only real flaw I have with the story here - because of the short run time of all of the cutscenes combined (30 minutes), the writers were limited. They were clearly trying to do more with certain character developments and the backstory of the Deadly Six, but it seems like they were cut short by the run time. It's nowhere near as bad as Colours and Generations, as they do get some very satisfying and thought provoking scenes in, as well as the expected comedy, but I can't help but feel there is still a LITTLE something missing. I don't blame the writers for this though, more the way the levels are structured.