This disassembly was generated with use of "Neto Assembler Editor v0.14a" Sonic 2 Beta (revi 14/09/1992) disassembly You can view all levels of this beta in "Neto Assembler Editor". Run "Neto Assembler Editor" and then Click in Tools -> Sonic Series Level Layout Editor and Load File "S2140992.epr" Neto Assembler Editor v0.14a Enjoy!
There are some data that indicate a possibility of another build between Alpha 21/08/1992 and this build was made. Starting from address 0x3B320 to 0x3B3B0, you will see some PLC pointers which are not referenced by main pointers. 0x3B3BA To 0x3CFEA - Unreferenced dynamic art data from Casino Night, Chemical Plant and Neo Green Hill. 0x3CFEA To 0x3F0EA - Unreferenced Angle Map and Colision Array Data. 0x3F0EA To 0x3FFEA - Unreferenced Colision data from Green Hill, Metropolis, Hidden Palace and Oil Ocean. 0xE502C To 0xE1DDE - Unrefereced data from Special Stage which has overwritten by current build. 0xE663C To 0xE8000 - Another set of Special Stage data from a possible previous build which has overwritten by current build. Other curiosities like the Object 0x62 which has no reference in final build and in this build is Timer Countdown in Special Stage. Object 34 - Title Card is Still using the Sonic 1 object and has the Oval and "FINAL" Mappings present. Some Art for Hidden Palace has some changes like Rinhobot enemy. 0x4D46E - Hidden Palace level layout is a copy of 0x4D7EE - Oil Ocean Act 1 Level Layout.
I wonder, have you looked into the 1992-08-21 prootoype, and if so, have you found anything interesting in that build? IDK why, but I am REALLY curious about what things might be lurking between the Wai proto, and that one. EDIT: changed "porto" to "proto" - damn, I swear, finger dyslexia has to be a thing. XD )
