This game is the most overhyped game ever, it is not one of the best Sonic games.
The combat is fun, and I love the enemies, but the writing is whatever, and the boss fights are AWFUL. Don't get me wrong, the music is absolutely phenomenal, but the gameplay of the bosses is just so BORING, it just feels like mindless button-mashing.
This game is just an ok game at best and a really mediocre one at worst.

Also, a very bold move by SEGA to make an open-world game that looks like shit.