Feral Interactive has released Mini Ninjas (http://www.feralinteractive.com/game/minininjas) for Mac OS X 10.5.8 and higher. The game costs US$39.95; a demo is available for download.
Here's how Mini Ninjas is described: "In Mini Ninjas you play at first as Hiro -- the last and best hope of the ninjas. Hiro’s been sent on a quest to defeat the Evil Samurai Warlord, whose otherworldly armies are wreaking havoc across the empire. As you journey with Hiro through lush landscapes and creepy castles you’ll find your missing ninja comrades, taking control of them and their unique skills in the battle to restore the balance of nature."| Read more »