NB. This is a review of the wiiware version of the game, any differences between this and the psn, xbox arcade and iphone versions will not be covered as I have not played any of them.
But right away this game feels so right. There are no proper cutscenes, no voiceacting, no extra characters - just Sonic, Eggman, badniks (for those not as familiar with classic Sonic terminology - the robots with animals trapped inside), chaos emeralds and a whole lot of rings. Despite it not being the full Sonic 4 experience there's still a good amount of content here - 4 zones each consisting of 3 acts and a boss, a final stage and 7 special stages. This game even includes the ability to play as Super Sonic after collecting all 7 chaos emeralds! As far as Sonic's abilities go he's back to just jump, spin dash and the inclusion of the homing attack (with I was initially skeptical about, but not fully understand the inclusion of). A minor gripe is that as Sonic falls he now comes out of a ball (leaving him vulnerable), but the inclusion of the homing attack makes instant death less likely once the attack has been properly mastered. The speed of the game is just wonderful, managing to maintain the speed a Sonic game should have without becoming too hard to follow or having the player lose control and fall into a bottomless pit. The special stages are a nice twist on the originals from Sonic 1 - only this time you control the tilt of the level rather than Sonic himself. So far I've only got 4 emeralds and they're becoming increasingly challenging - something that makes for a good replay value once you've finished the 4 zones.
The only main problem I have with this game (and funnily enough its also the exact opposite of what was wrong with every other recent Sonic game) is it's lack of originality. The levels are in some instances carbon copies of classic zones, there are no new badniks present in the game whatsoever and the bosses are the same other than the fact is they get an update toward the end (Green Hill, Casino Night, Labyrinth, Metropolis and Sonic 2 Death Egg zones to be precise). If I wanted to play these bosses, I'd play the original games. I'm all for homages as the next person is, but what I wanted to see was a classic style Sonic game with some new ideas, not constant throwbacks and updates to the originals.
Despite this, Sonic 4 is without a doubt the best Sonic game in a long long time and if episode 2 can fix the problems this episode has, we'll undoubtedly be looking at the best Sonic game since the Mega Drive era. Welcome back Sonic the hedgehog. You have been sorely missed.