I was gonna make this thread after I had it for a while, but yeah you pretty much broke it down. This game is basically a tribute to 2 generations of Sonic fans; those who grew up-came of age during the 90s, and those who were kids during the DreamCast/Xbox 360 era.
There's a little bit of something for everybody in this game, and what's great is that the game is challenging without being too overly frustrating. Will you die a few times? hell yeah. Will you have good runs, only to lose all of your rings like the "olden" days? You got it. And you'll love every minute of it.
What's really cool is how they used Sonic's old levels, but based his "Classic" form off of an Arcade Game from the 90s called SegaSonic The Hedgehog.