When it comes to the main characters, Impact does a good job of portraying them both visually and audibly. Each character continues to be voiced by their American translation actor, while the models themselves look just like they should. Its the rest of the game that makes Impact bland ...both on a presentation level and a gameplay one.
Most of the game consists of fighting hordes of cookie-cutter ninja that all look exactly the same. While most of the time you will be fighting the same bland enemies, there are occasions where you will fight multiples of some of the named characters as well, like Sasuke fighting tons of Naruto clones. Even then, the fights consist mainly of wave after wave of the same model. As a result, you tend to feel like you aren't really making any progress, even if you've mowed down dozens of enemies.
The rest of Ultimate Ninja Impact's audio does what it needs to do. The standard Naruto music is accompanied by a variety of sound effects, but much like the rest of the game, there isn't anything here that makes Impact really stand out. Though there is one aspect that gets annoying pretty fast, and that's the one-liners spouted off by your character or one of the other main characters in the mission. The various characters speak up often, but none of them seem to have a wide range of comments to say. As a result, you will hear a character make the same remarks over and over again before you are done with a level. In the end, the game might as well be played with the sound turned off.