"DU: The Gunstar Heroes' Battle of Rapid River" - this bit did okay this time around. ;-)
>ShouTime got Rapid River (Japan).
Good to see alternate regions being found.
>colour_thief got Gunstar Heroes (Mega Play).
Congrats with this long time elusive game finally being found. The various hardware part numbers for the game will be ideal if they can be added to the source file. At least this appears to wrap up of finding all the games for this particular hardware. I hope same success will be possible with the remaining megatech hardware cartridge games yet to be found.