I've watched all the cutscenes already. And I have just one thing to say about Colors regarding it;
Best.
Storyline.
In a Sonic game.
Ever.
Seriously, I loved Adventure, I loved Unleashed, I quite enjoyed Rush and Chronicles. But this? This just takes the cake. The story is like a more serious version of AOSTH; plenty of humor, but without all the...squash and stretch wackiness of that particular show.

I have to give credit to the writers - they crafted a very nice little tale for the fans. While I can, say, sit through Adventure 2's halfway boring story almost straight-faced, Colors, on the other hand is actually enjoyable!
I don't think there wasn't a moment where I wasn't cracking a smile or chuckling at the very least, save one or two instances were I was a bit in suspense! And the characters have...
character! They aren't simply cardboard cut-out with a few layers of depth. They're 3D, well-rounded characters! They have personality! You can thank the voice actors for that for one. Roger's got Sonic's cockiness down to a T, and Kate makes Tails sound better than he has been in years!
The writing had a hand as well. Occasionally, Sonic and Tails will drop casual remarks to each other that though don't always have anything to do with the threat at hand, give you good insight into the character's personalities. And speaking of Sonic and Tails, the relationship between the two is better than it has been in years!
Speaking of evil, Mike Pollock also does a great job with Robotnik here. Definitely more AoStH than SatAM, but he's clearly still a respectable threat. And those two robot henchmen... Scratch and Grounder, anyone?
Mike Pollock is awesome as Robotnik. He's not Jim Cummings, but he does a great job all the same. And I
love Orbot and Cubot. ^_^ Those two are awesome.
All in all, I'm very impressed with how the story came out. ^_^