Everything I have to say about the game is HUGELY positive. Its exceeded all of my expectations and then some. Im not finished the game yet, but so far its out of this world. Can see why its the highest rated Sonic game in 15 years. I even illustrated my feelings in this chart...
They unlock stuff in the Extras menu and in No Save games. You only need golds if you're going for the trophy, silvers will be enough to unlock everything
I was a massive fan of the four megadrive (genesis) games and this is a true sequel to those. Plays great. Solid amount of (large) zones to play through, fun extras, and player 2 can still pick up the pad and play the second character!
I don't take issue with the 3D sonics, they're just not for me, but sonic 4 was a pretty poor attempt to do the old school 2D stuff, so this is amazing. Very happy with it.
Here's a cool thing people might have missed, back in the original games player 2 could fly sonic around using tails, but in this release even playing with sonic and tails but alone with no one playing tails on the second pad you can still do it! Press up and double jump as sonic, and tails will start flying, then jump into his hands and you can control tails flying you where you want to go! No second player required. Nice cool little feature.