Recompiling old GBDK games into Game Gear ROMs

Hello!
I'm currently trying to develop a compatibility layer to compile GBDK games to devkitSMS.

https://github.com/haroldo-ok/sms-gbdk-compat

This is a work in progress. So far, only the 'galaxy' and 'dscan' examples have been tested; they still needed some minor changes to the source, but the compatibility layer did save a lot of time.

This is a great idea! I wonder how far off the idea of semi-automated disassembly and Graphics/IO/Sound-adaption could be done for a commercial game like Tetris.

Well, a tracing emulator could detect which parts of the ROM contain code and which contain data, as well as which parts of the code are trying to access the vídeo RAM.
Translating CPU instrucions would be trivial, since they are so similar. Then it would be necessary to translate VRAM accesses to the equivalent VDP commands, which should be slightly more challenging.