Capcom adapted their popular Mega Man games for the Nintendo Entertainment System into Game Boy counterparts that mashed up elements of the first four games in the series in unexpected ways allowing for, say, Cut Man and Heat Man to exist in the same game.  Want to shoot Fire Man's weapon at Quick Man?  Go for it!  Mega Man V, however, was an entirely new adventure with original elements, and after that the handheld series went on hiatus.  No Mega Man VI.  Certainly not a Mega Man VII.  And definitely not a Mega Man VIII... unless you count this bootleg knock-off version cobbled together from bits of Mega Man III for Game Boy and the real Mega Man 8 for the Sony PlayStation and Sega Saturn.  Check out this video of Rockman 8 for the Game Boy from Makon Soft and watch for oddities that imply the creators were either confused about Mega Man or just plain didn't care.  For instance, because Mega Man's portrait is traditionally in the center of the stage select screen, the creators assumed that he's an enemy Robot Master with a stage all to himself, so selecting that portrait brings up a Rock Man stage.  Here's the Bootleg Games wiki to fill us in:

The engine contains many glitches throughout. One serious glitch is that sometimes, after killing so many enemies all of the remaining enemies and moving platforms disappear, making the level impossible to complete. Another major glitch is found when battling the boss on Clown Man's stage, where the game will sometimes reset itself without warning. Rockman's health bar is bigger than normal and he can't collect any weapons in this game, nor does he have any extra weapons at the start. As a result, he only has the Mega Buster and the pause screen is blank, aside from showing his health bar. Charging up the Mega Buster is completely useless, as a charged shot does no damage. As there's no weapon energy, all of the items refill Rockman's health. The graphics are taken from the Rockman games and simplified. The music is poorly remade from Rockman 3 and 4. There is no ending, with the game going back to the robot master select screen after beating all of the bosses.

It's fun to point and laugh at pitiful attempts to con the audience like this, but just think what Capcom could have really accomplished with a Game Boy (Color, by that point in time) version of Mega Man 8.  I bet they could have created a game that maintained the spirit of the original game meshed with the classic NES/GB style.  We'll never know, but there is a fan-made demake of the PS1 game for PC that converts it into the traditional 8-bit style and structure that comes what I have to imagine is pretty close.