Reverse Engineering Sonic 2 Special Stages?

Discussion in 'Engineering & Reverse Engineering' started by slinga, Sep 11, 2019.

  1. slinga


    Hi all,

    I'm interested in reverse engineering and eventually decompiling the special stages for Sonic 2. I'm looking for some advice on how to get started. I have successfully loaded Sonic 2 in Ghidra for both the Sega Genesis and Sega Saturn (via Sonic Jam). I plan to play in an emulator and set breakpoints to figure out what code is being executed during the special stages.

    1) Are there any notes available on previous efforts to analyze the special stages?
    2) I found flamewing's s2ssedit and that's giving me a good place to start. I will spend some time reading through his source code.
    3) The "misc" directory in the Sonic 2 disassembly doesn't make much sense to me. The .asm files don't appear to have useful instructions. I'm just seeing a bunch of dc.w instructions without any branching.
    4) Also in the "misc" directory, I haven't been able to decompress the Kosinski compressed bin files. I tried accurate-kosinski but it didn't output a file. Any notes on what these files are for?

    Thanks in advance.
  2. MainMemory


    Have no fear...Amy Rose is here! Tech Member
    Those ASM files are the paths for the tubes in CPZ and MTZ, they are stored as ASM for ease of editing. As for the Kosinski files, they seem to decompress fine with FW-KENSC.