Known as Sega CD in the US, this was not just a CD drive for the Mega Drive: it added a faster CPU, new graphics and audio processors, and more RAM. All this power was mostly wasted on hilariously cheesy FMV "games"; nonetheless, this system had a good number of quality games. It could also be combined with the 32X to form a behemoth of a system for which only six (terrible) games were made. PROTIP: as the Mega-CD was released long before CD burners became popular, it has no copy protection system. Still, the games are region-locked, and it takes modding or a special cart to bypass that.