Case 1: The extra roll tunnel
In the Beta, there is an extra roll tunnel (the one just in front of Sonic) at the start of act 2.
Case 2: Roll trunnel beta properties
In the Beta, Sonic does not curl up in to a ball when you enter a roll tunnel. You can run through them like in Sonic 2 beta.
Case 3: Extra Flowers
In Sonic CD beta there are unique flowers for each level. These are the ones found in Collision Chaos.
Case 4: Electrocution
In the beta Sonic can be electrocuted by Metal Sonic. Also, before Metal Sonic breaks thought the spikes they are normal upwards ones. In the final the spikes are sideways.