Quite Good if you play it as it's meant to be played...
Graphics
The graphics in the game are quite bad at in night missions(most missions) but suprisingly good in daytime missions(few missions).
Sound
People in the game speak Japanese so there is no bad voice acting, the sound effects are quite good.
Gameplay
The gameplay is good if you play it how it's meant to be played. Using lots of cool equipment such as shurikens, guns, disguises, traps and many others. If you just run through the level it won't be much fun as the combat is slow and lame. Try earning a Ninja 5 ranking in each difficulty on Hard, you'll have to use your equipment. After each mission you get cash which you can spend on clothing, equipment or skills. Skills include wall running, ceiling climbing, rappeling, invisible cloaks and others.
Overall the game is worth a buy