Sega Master System / Mark III / Game Gear
You're Joe Mushashi - a mean, black-clad ninja dude, who must travel the horizontally scrolling levels using your ninjitsu skills to blat the baddies and rescue the kidnapped kiddies. There's also a shunken shooting range in there, where our hero cnucks death-stars at the evil henchmen. Six twisted arch-villains also make an appearance, and a different beat 'em up tactic is required for each one.
Sega Shinobi is a great conversion of a decent coin-op, with literally hours of beat em up action jammed in. Shinobi has great graphics and jam-hot playability, and since there's hardly any decent Sega beat 'em ups available, there's no excuse not to add this one to your collection.