On principle I don't really like the idea of Sonic being sent after Shadow at the request of G.U.N for two reasons: But depending on what the surrounding context is, I can see how the movie could make this plot point interesting in a completely different way that still complements these versions of the characters, even if I don't prefer it to the original. So, some ideas: Now, this puts Sonic in a fascinating position, particularly when using the game as a frame of reference. SA2 was very straightforward with how it presented its conflict at first: you have a Hero Story and a Dark Story, and as such you're primed to think of everyone on both sides as either being good or bad. And most people, I think, were inclined to play the Hero Story first; it's the one with Sonic in it, and the select screen hovers over it by default, too. It tells a very simple story of Sonic and friends stopping Eggman's (admittedly very threatening) evil plan, developing some new rivalries along the way. It's already a little bit of a twist for Sonic and Knuckles to have formed a respectful relationship with Shadow and Rouge by the end, since you see them as villains initially, but they still remain antagonists. Rouge returns the Master Emerald pieces, but she's still working with Robotnik. Shadow thinks Sonic is pretty impressive, but he still tries to kill him to stop him from saving the world. But then you get to the Dark Story, and then the Final Story, and you think, oh. It's really not that simple. For starters, you get to see more of Rouge's bond with Shadow. There's some conflict inherent to their relationship because Rouge is a spy and is only here to get information on Shadow, but after he saves her life, there's a definite shift to their dynamic. There's something genuine there, even if it doesn't get a lot of screentime dedicated to it. But most important to the story is what we learn about who Shadow is, in part through his interactions with Rouge. Shadow is cunning and ruthless - heck, his goal is to literally blow up the world. But whether out of compassion or survivor's guilt or both, he can't let Rouge die, so he saves her and then lies about his motivations for it to seem colder than he is. And even though the things he's doing are definitely bad, his motivations are famously sympathetic; he wants revenge for his best friend, a young girl who was killed by the G.U.N military during a raid. (It was implied that there was some sort of brainwashing done on him by Gerald after Maria died as well but that part of the story is incredibly vague) By the end of the game, Shadow comes into his own as a hero and helps save the world instead of destroying it. And suddenly it makes sense why the stories weren't called Hero and Villain, because neither Shadow nor Rouge are especially villainous characters; Rouge is selfish, and Shadow is driven by grief and hatred, but they're ultimately kind at the end of the day. Both of them find people to care about - each other, as well as Knuckles and Sonic respectively. But y'know, there wasn't a lot of ambiguity about who the heroes were in the Hero Story itself. Sonic, Tails, and Knuckles are pretty clearly The Good Guys, and nothing they do is really questioned because they're always fighting The Bad Guys. So what I'm seeing here is an opportunity for Team Sonic to not be totally in the right for once. Yes, it's good to stop Shadow from going on a rampage and destroying the world, but look at who they're keeping for company here. G.U.N? Robotnik and Agent Stone? As if either of those groups are trustworthy enough to not stab them in the backs as soon as it's convenient. As if they're not going to find some way to exploit Sonic for their benefit. And frankly, Shadow is totally in the right to hate G.U.N, and Team Sonic for working with them. Given that his backstory seems to be largely unchanged, it's kind of impossible not to be on board with him fighting the protagonists at least a little bit. Besides, I don't think it's a coincidence that Shadow is doing the wrong thing for the right reason, while Sonic is doing the right thing with the wrong people (and maybe also for the wrong reason). That has the potential to be very clever if executed well. I can only imagine the dawning horror on Sonic's face as he realizes just how much he's not on the right side of this conflict; when he learns about what happened to Maria and everyone else on the Ark. Especially if Tom's family was involved in it, like the current popular theory going around. Also, last-second realization: what if there's something more to that line from Tom, "it wasn't always easy, but you didn't change who you are in here"? Most likely it's going to be used as a way to show how Shadow is different from Sonic, because he did change who he was in response to trauma and it'll be really poetic when he "finds himself" again But also, consider: maybe Sonic does end up changing throughout the movie. Maybe he does something that goes against his core principles in order to get an advantage in some way, and they kind of play around with the idea that Sonic is similar to Shadow in ways that aren't always flattering to either of them. I want those hedgehogs to make each other worse before they get better In any case, there's a lot of potential here, and I'm very curious to see what they ended up going with
See Also
15 Things We Noticed In The New Sonic The Hedgehog 3 TrailerTails (Sonic Cinematic Universe)The 10 most iconic video game final boss fights of the 90sIs metal faster than Sonic? - Games Learning Society