Fans of the series finally get what they want: less flash, better gameplay.
...15 years later....
The first official sequel in over 15 years has been released, and it is everything that Sonic the Hedgehog should be. Remember when, after several poor 3D iterations of Castlevania, Symphony of the Night came out and fans rejoiced at having their series back in 2D with that familiar gameplay. Sonic 4 gives that same kind of feeling. It's just like picking up the very next Sonic game right after Sonic and Knuckles, the same kind of feeling as when you picked up Sonic and Knuckles after Sonic 3.
The game actually plays more like Sonic 1, with only Sonic available for play this time around (maybe that'll change in later episodes). Gone are the various shields and special attacks of Sonic 3 and Knuckles. However, Sonic now has a homing attack that can zero in on certain area of the levels, like springs, and enemies. The familiar shoe, invincible, and shield powerups are available, as in Sonic 1. And everything is presented in a wonderful 3D animated, 2D style gameplay format. In addition, the stages are familiar to Sonic's typical stages from various games, but with a decent variety of stage elements to keep things fresh.
Unfortunately, there are some elements that would have been great to have, such as Sonic's buddies, the aforementioned power ups, and the game tends to feel a tad slower than you would expect of a Sonic game. But that's okay, because the game is pure fun and quite the nostalgic trip. Any fan of Sonic the Hedgehog would be committing a crime to pass this one up, while anyone too young to remember Sonic should pick this up so as to find out what all the popularity is about, because this is one game that's bound to become a treasure.