Recently, the second episode of Sonic the Hedgehog 4 came out. You may recall that Sonic the Hedgehog 4, Episode I reused bosses, though it gave them a new lease on life with a sort of berserk mode when highly damaged. It showed that Sega could still do what had performed the best, though the physics were a bit a wonky, and Sonic felt somewhat sluggish.
I have a policy of 2 good guys, 2 bad guys, and Knuckles allowed in any one Sonic game. They are within limits still. You start pullin’ Big The Cat on me in Episode 3 and I am OUT.
Episode 2 remedies that, and it feels much livelier and more controlled. Tails makes his return in much the same fashion as he accompanied Sonic in Sonic 2 and 3. In singleplayer, he dutifully follows your motions, and you can now even tell him to pick you up, pull you through the water, or combine into a deadly rolling ball of ridiculous.
By the way, they upped the ante on the bosses. This is the FIRST.
The newer mechanics are used well and the levels flow. It’s Sonic: How it’s supposed to be. Additionally, for the first time I can ever remember, I encountered a Badnik that took more than one hit to take out. He was a biggie, but no mini-boss, just a normal enemy. I guess Sega can change things a bit.