That is fairly spectacular; it looks as if it is primarily two video games in a single! I used to be anticipating it to be a fast 2-3 hour expertise, however it is a nice shock. Contemplating the tempo at which the degrees progress, I am guessing this contains the usual bonus missions as effectively although?
So long as it exceeds the period of the Mission Shadow DLC for Sonic Forces, which is about 20-minutes over three ranges, then it positively sounds promising!