Sen would have looked right at home on the PlayStation 2. Textures and environments are dull and uninteresting, and the characters move with a stiffness that is uncharacteristic of the genre. However, I do like the menu screens; the hand-drawn vibe resonates with me the same way that Okami (a far, far better game) did. No Japanese game is complete without a torrential downpour of cherry blossoms. Consider Sen complete, if only in that regard.
I wouldn't say that Samurai Shodown Sen sounds bad, and I definitely wouldn't say that it sounds good. It's kind of in the middle of the road. The distinctly Japanese soundtrack blends well with the rest of the game, and the clashing of weapons sounds alright. Voice acting is exclusively Japanese. Since a lot of the story and character-based content doesn't read well, that's probably for the better.