I have Sonic Generations 3DS now, and to be honest I'm less than impressed.
The opening three stages for Classic Sonic, in fact are directly remade from their Genesis counterparts. Later Classic Sonic levels introduce a homing attack and make little to no effort to make it play like classic Sonic.
The game is full of pitfalls and cheap traps, no surprise considering this is Dimps, but unlike the console version where it is generally okay to miss a chance to get onto a better platform, failure to hit some of these events will cause all kinds of problems.
Suppose you don't hit a ramp at full speed, Sonic will travel across a gap but not all the way.
Lemme tell ya, Radical highway is pissing me the fuck off, it's offering some of the worst Dimps has. Remember those
gold beetle enemies in Sonic Adventure 2, that would go away if you didn't get to them fast enough? They are practically IMPOSSIBLE to reach in this game because they appear far before you can even get close to them. It's dreadfully designed. This game doesn't place any safety nets up, rather than allowing the player to perform somewhat poorly, they insist that you fall to your doom repeatedly.