Sonic Forces aka Sonic Project 2017 was officially shown off at a recent Sonic event. Lots of details and information was released, so we will be breaking it down.
First is the gameplay trailer, showing off how Modern Sonic plays in the game. He mirrors the Generations/Unleashed gameplay style heavily and the level shown off presented the blue blur speeding along at high speed. Level design doesn’t look that impressive at first glance but this is likely the very first zone, so it’s easing the player along until more complex level designs open up. Generations comes to mind, as while Green Hill Modern was very linear, the other Modern Stages were far more open. Also helps that the level shown off seems to span miles upon miles, larger then any other Sonic level shown thus far.
The wisps are back too, as Sonic is seen collecting white wisps before boosting, implying that boost is tied to the creatures like in Sonic Colors. Maybe other wisps will return and we will likely know more in the future. Sonic is the only one playable, as both his Modern and Classic incarnations will be featured in the game. A third play style is happening but no information on that has released. It’s speculated that a new character or ‘Boom’ Sonic could be the third style but that is just guessing on my part. 
Graphics and effects are another factor to consider as well, as it fantastic. Slash effects when Sonic races across puddles, explosions colliding with the landscape and lots of visual information in the background present a large-scale battle while you race through the stage. Story was detailed as well, with the game taking place in a time where Eggman has won. Sonic and friends are working together to put down Eggman for good, with radio chatter (not unlike in Sonic Heroes) playing in levels as Sonic runs through them. So the plot will be major in this title unlike past Sonic games.
Music is impressive, with a main theme (demo version) being released and the music playing in the gameplay clip sounding distinctly Sonic. The main theme is clever too, blending classic and modern sounds perfectly together, closing with a beautiful piano piece at the end of the track. Vocal themes are going to be added in and Crush 40 will be working on the song. 
Overall, the game looks promising and we will likely learn more in the coming months during events like E3 2017 and within Sonic-themed events. Stay tuned for further information and gameplay.