Sonic the Hedgehog 4 Episode: II

[Gaia]

It's all 3 aspects actually: physics, which are then complimented by level design, and speed which is obtained by a combination of both.

If I may interject; 3D Blast was a bit too fast, because for one you can't see where you were going top speed most of the time and there was a high chance of hitting a landmine, and then the best part for me (for most sonic games sans this one) was the chaos emerald system. Sadly 3D Blast decided to go the S3K route and hide them, top it off it was too fucking easy.

It WAS innovative in a sense, just overlooked with those innovations.

Back on the subject, the Hedgehog Engine is a GRAPHICS engine, not a physics engine. WHY DO PEOPLE KEEP FORGETTING THAT... GOD!