This adorable hack-and-slash title starts out with a pretty basic ninja story: a long time ago, an evil samurai warlord wreaked havoc through the countryside. A group of ninjas managed to defeat the warlord and banish him, allowing a period of tranquility to settle over the land. Recently, however, the old ninja master has felt a disturbing unbalance in nature, so he sent his students (one at a time) to investigate. His students have disappeared, one by one, and now he is left with his final two students, Hiro and Futo.
You start out as Hiro, the youngest and smallest of the mini ninjas. Hiro may be young and inexperienced, but he has a gift for Kuji magic, the same type of magic that the evil samurai warlord has been using to amass an army (of woodland-critters-turned-samurai). As Hiro starts out on his journey, he rescues his ninja friends. As he rescues his friends, you are then able to switch between Hiro and the other ninjas. Each ninja has his or her own initial attack, stun attack (for stunning the opponent so the initial attack can deal a more powerful blow), and power attack (a special attack that the character can do using the "unstable Ki" or red energy spheres.
Gameplay is pretty simple. To move your character, simply aim the mouse and use A, S, D, or F. Space bar will let you jump or interact with characters/items. Fighting is also pretty basic; the left mouse button will take out your weapon and perform the initial attack, while the right mouse button will perform the stun attack. To use your power attack, hit Q and then the right button. To switch between characters, hit "1" and click the character you want to switch to; you can do this at any time, and each character has strengths and weaknesses.
Fighting is easy, just point your mouse in the general direction of your enemies and hit the buttons. There are situations in which strategically timed power attacks or spells will aid in defeating enemies, but blindly pointing and clicking will get you very, very far. Also, if you're squeamish, you have nothing to fear because the samurai don't die, they just vanish into a poof of smoke and reemerge as adorable little animals.
While Mini Ninjas is a fairly linear game, there are plenty of little nooks and crannies you can explore. For example, you can search for Kuji shrines (each shrine will give Hiro a new spell), money, and potion ingredients (such as flowers and mushrooms). The money and ingredients can be turned in at outpost shrines for helpful life-bar potions.