The aim of this mod is to improve Classic Sonic's gameplay in Generations. Note that this doesn't mean he was bad in the original game. This mod simply makes some tweaks and changes to make him play more like one would expect.
Here's a list of some of the changes.
Classic Sonic more closely resembles his renders.
Classic Sonic controls more like the classic games.
His jump is lighter.
Spindash is nerfed to feel more like the classic games. (OP SPINDASH IS OPTIONAL!)
Sonic is much less prone to uncurling after spindashing / rolling.
Rolling feels more like the classics and can even keep speed down steep slopes.
Springs function more like the classic games.
Shield monitors are actually present as power ups within stages.
Removed a lot of scripting.
Super Sonic is faster.
Some (personally) unfitting elements in stages have been altered. Such as the realistic birds in SSZ being replaced with the more cartoony flickies.
Various other changes!
There are a few different versions to choose from. One of which is a version with absolutely no graphical changes so you can play with that if you don't want any of those! Another version is what is essentially and override for the original game's OP spindash. Load that first in the mod loader to use the op spindash. If that doesn't work try moving "#SonicClassic.ar.00" from the disk/bb3 folder (from the op spindash override) into the same folder for the actual mod to replace it manually.
To use this mod alongside custom stages then try loading the custom stage mod first in the mod loader. It should overwrite any files it needs to function.