Originally an exact copy,
then palette swap of Mario, Luigi was created to facilitate a second player option.
Not exact matches
Since
then, he would become a regular playable character, and one of the many, many
palette swapped ninjas.
Clearly the HuCard medium wasn't big enough, since whereas the PC - 88 and MSX2 versions had at least 38 unique enemies, the PC Engine game has at best maybe 15 which
then undergo repeated
palette swaps.