The side scrolling bits in Generations would have been fine if they'd got the physics/movement right on Sonic. To me that's what made the real difference with the originals (and should do with Mania as well) - the controls were spot on for Sonic. He may have moved fast but you felt like you had the tools to control that movement.
3D sonic has always been a ball ache to control, he's a floaty bastard who decides to fall off/through things whenever it suits him!
Had a bit of a play - so far it's decent. Pretty much Sonic Generations again but it feels a bit low budget somehow. Not sure why but the menus and the game just feel a little lacking in polish compared to Generations.
The bits with your own character seem a bit of a pointless addition but on the plus side they play ok so far and aren't annoying like say the Werehog.
So yeah from the first 4 or so levels I've played it's a solid 7/10 so far. Nothing wrong with it as of yet really other than could do with a bit of polish. Guess for £24.99 though a few rough edges are to be expected.
I got this on Saturday and have played 20 stages so far. You get to difficulty choices, normal and hard, but you can only be on the ranked leaderboards if you play on hard, which is the default setting. Hard mode is really easy so I dread to think how easy normal mode is. The only times I've died are due to falling off the edge, hitting an obstacle I didn't see due to the speed, or killing myself as I missed one of the red rings and that only way of getting back to it quickly. I even got an S rank on one of the levels I died on.
Classic Sonic in the side scrolling levels handles terribly. He can't jump that high, but despite this, he's still too floaty meaning it's very easy to misjudge a jump over to a platform when you're trying to reach a particular part of the level.
The most enjoyable levels for me are the ones where you have to use the character you create yourself as you have a weapon and it adds more to a level than just running, jumping and doing homing attacks on the enemies.
Despite all it's flaws, it is actually quite enjoyable to play, but it's definitely not worth more than £25 which is what I paid for it.