While I'm a huge fan of Unleashed and Generations, which both used the same general game play formula Forces does, Forces appears to have dumbed things down. Significantly.
Modern Sonic doesn't have the drift anymore, nor can he Lightspeed Dash, so that's already two moves removed from his repertoire that limit level design possibilities compared to previous games.
As for the level design so far, even in the Modern Sonic and Avatar stages, there is an over-abundance of 2D sections. This is supposed to be the big 3D Sonic game that follows up from the Classic Sonic revival in Sonic Mania. Not only have they got Classic Sonic in Forces, who is fully 2D, but most of the Modern Sonic/Avatar gameplay shown so far has been in 2D. The only fully 3D stage so far has been the Tag Team stage. Sonic Team just has this unhealthy obsession with including 2D sections in 3D Sonic games and it needs to stop.
As well as this, even the general level design of Sonic Forces seems dumbed down, regardless of whether or not it's in 2D or 3D. 2D sections use very simplistic block platforming like Sonic Colours had, and people criticised that game for that, so it's annoying to see that back.
As for the 3D sections, well... Just compare...
Sonic Forces 3D sections are the literal definition of straight line hallways in all the gameplay we have seen so far, there isn't any vastness to them and there rarely seems to be alternate pathways or areas that organically intersect with each other that made the stages feel open on Unleashed and Generations.
Even the Classic Sonic gameplay has severe automation issues where they have sections that look like a cool, momentum based set piece, but right at the end, an invisible spring will pop up out of literal THIN AIR (as in, not even stuck to the ground) to launch you to where they want you to go. They don't trust their physics engine to naturally do the job through momentum and inertia.
I'm excited for the story and the characters and the music but the gameplay has so many baffling regressions that look like a bastardisation of the games this one is supposed to be building off. It's like, they saw what detractors of the boost games would say about them, even though those accusations weren't true...but decided to actually make them true.
