Play Ninja Spirit Online

Ninja Spirit on Game Boy is one of those classic, no-nonsense action games where you slash your way through waves of enemies as Moonlight, a ninja out for revenge. You start with just a katana, but pretty soon you're tossing shurikens, dropping bombs, and swinging this gnarly sickle-and-chain thing—each weapon actually matters, too. Some enemies just laugh at your sword until you hit them with the right tool.

It's tough, no question. No saves or passwords here—straight from the arcade like that—but at least you can tweak the difficulty if you're not up for the full punishment. The first level lulls you in with basic foot soldiers, but by the second stage, you're already dodging arrows and figuring out which weapon clears crowds fastest. That sickle has surprising range, by the way.

If you like your ninja games fast, loud, and slightly unfair in that old-school way, this one's a solid time capsule.