From Sonic Retro
Unused Items
Dude2004 found several unused items in the PC port. These items were a Button (Aoki Switch) from Lost World which has two types...push and toggle type, Tumbleweed from Windy Valley, Trashcan from Speed Highway, and Icicle from Ice Cap.
Duplicate Casino Geometry Data
If you enter and exit the Casino area, copies of the casino geometry will appear at their global location, providing proof that the adventure fields were originally meant to be built as one piece, but then segmented for efficiency (the SA engine had a hard time rendering things before it got the DX upgrade). The texturing is glitchy, as anything rendered by the SA engine is when it has erroneous texture refrences. It will frequently revert between textures, and sometimes even animate them.
