|Past and present, in perfect sync.|
Immediately when you press 'New Game', you're thrusted right into Classic Green Hill. After you beat it, a black cosmic tear forms in the sky, and we cut to the present, where it's Sonic's birthday, and his friends (and Shadow for some reason) are holding a surprise party for him. Then, the same tear from before appears and seems to be some dark robot monster... thing. It sucks everyone but Sonic into portals, and Sonic gets knocked out and awakens in a White Space. He now has to revive all the zones that have been transported there, along with his friends, by completing all the acts in the zones with his Classic counterpart. I don't want to spoil too much, but Eggman is kinda important.
The gameplay is obviously split into two types: Classic and Modern. Classic Sonic plays just like in Sonic 2. He can jump, move, spindash, and not much else. Modern Sonic plays more like recent games, like Sonic Colors. In 3D, you're constantly moving forward, dashing through enemies, outrunning obstacles, that sort of thing. In 2D, it's just like the 2D in Sonic Colors; basically the same as Classic Sonic, but you can Homing Attack, Stomp, and Wall Jump.
As you progress through the game, you gain points, which you can redeem at Omochaos's shop (just to the left of Green Hill) to get power ups that you can equip to both Sonics, such as Flame Shield, Speed Boosts, and a barrier at the start of the level. If you go further left, you can go to the Collection Room, where you can view the pictures, songs, bios, and videos you've unlocked by getting Red Rings.
The music combines the best aspects of all the music in the Sonic series to date! Considering it has some of the most popular levels from the main console games, it's to be expected. Each stage has a Classic and Modern version of it's song, which plays during the corresponding act. You can also change the music to a track that you've unlocked. I really like that option as it adds variety to the soundtrack.
Overall, I'd have to say this is the best Sonic game released since Sonic Adventure 2. I dare say this is the best Sonic game ever! Of course, that's assuming the future titles are gonna be shit, which I doubt all of them will be.
HBM, signing out!