Was this going to be included in a European version of the Smash Pack or was it another Genesis emulator for a different Dreamcast release?
Supposedly it was going to be a Mega Drive collection for Europe, which never saw a release Sega Smash Pack Vol.1
Can the emulator be manipulated or 'tweaked' for personal use? (DreamONGen II springs to mind).
So far, this is what I have figured out:
There's a ROMs folder where you can place your .BIN format Genesis/MD ROMs.
In the MD_EMU folder there's a file called ROMS.LST that has a list of all of the filenames of the ROMs in the ROMs folder, along with the filename. Here is an example snippet:
AfterburnerII.bin Afterburner II
aliensol.bin Alien Soldier
astorm.bin Alien Storm
ALISIA_D.bin Alisia Dragoon
altbeast.bin Altered Beast (smash pack)
arcade.bin Arcade Classics
bubstix.bin Bubba N' Stix
calgame.bin California Games
columns.bin Columns (smash pack)
The emulator is set to European region, but you can switch the region for a specific ROM to USA or Japan by prepending the #U or #J tag to the filename (See #UALADDIN.BIN above).
You can also prevent a game from displaying on the menu by prepending !, as in BLOODLIN.bin above, it was probably removed from displaying since it actually crashes on bootup.
From what I can see, the emulator is based on the same core as Sega Smash Pack's emulator, but this hasn't been confirmed. Given that there are references to the Smash Pack and the same ROMs are included as what was included in the Smash Pack, it's probably a correct assumption.
The one advantage known so far is that the region can be changed; on Sega Smash Pack it was locked to USA region you couldn't play any region-locked Japanese or European games at all without patching the individual ROMs to circumvent their region-checking routines. And, also, the menu looks a lot cleaner and polished and official of course.
The disadvantage is that the Smash Pack had tweakable graphics modes, sound modes, and frameskipping, and this one does not. Which is a tremendous disadvantage. However, japanese_cake did look at the code and determined that the emulator tries to load per-ROM configuration files in the format MD_EMUXX.CFG, but we don't know what options this presents nor the format for the configuration files. So, there's more work to be done here.