I'm sure the world is going to be empty minus Sonic and enemies. Again, I'm pretty sure that Sonic Team is looking SOTC as inspiration. That has been vibe I've gotten since the initial reveal.

Visual looks amazing

On a technical level, no obvious Sonic jank.

So far so good. 

Yikes, I've seen more and I'm not happy :'( 

Considering the speed it looks strangely relaxing to run about that world. Though stuff like drawing three circles to put out the flames seems more busywork than fun so the biggest thing will be how engaging the overall package is. They need to nail the physics or else it's gonna be a flop.

The graphics are very off putting imo. Almost too real looking. It looks like one of those tech demos when a new unreal engine releases except this is for the game and I don't like looking at it.

The art style might not be the best fit but this does look promising. And can people stop saying "breath of the wild" for every open world game? I would have preferred a more cartoony art style that matches sonic, but the gameplay looks crisp and fun. I have hope. I really like sonic and I'll keep having hope. What's the fun in being bitter about games anyways?

Why didn’t they go with cartoony looking environments?

The clash between Sonic and the environments is quite stark. They should have gone with something more in line with what Nintendo did with BOTW.

It looks like they took the easy route and went with the built-in assets of U5.

Even more of an Unreal 4 tech demo

The sheer amount of rails and platforms that looks randomly placed by the spagetti monster doesn't exactly fill me with hope.

I watched the gameplay trailer a few times but I have yet to see anything exciting. To me, it feels a tad out of place for what I expect an open world Sonic game to be. Like Green Hills from Sonic Generations kinda shows what I expect the world of Sonic to be:

Now obviously this is open world vs Generations is not but it's like... Where's the color? Where's the art direction and etc? Where's the charm? What about this game really speaks that it's a Sonic game? So far it looks like a randomly generated unreal engine map with no sense of structure with rails and such littered around the area.

Even the music feels out of place as Sonic games usually have a nice upbeat music to them. Not this random melancholic music. But we will see. Hopefully there's a lot more to it and the end product is good.

At this point, Sonic Team is better just letting fans remake Sonic Adventure 1-2.