Tekken 6's full motion videos look every bit as spectacular as they ever have. The energy is high and the animations are almost impossibly clean. On the game side of things, well, they also look great. The only criticism I have regarding Tekken 6's otherwise impressive visuals hearkens back to my main problem with the game in general: we've seen all this before way too many times. I'm probably being too nitpicky about the specifics, so I'll end with this: if you've played a Tekken game at least once over the past six or seven years, you know what to expect from the graphics, and you know they are good.
One thing I've always loved about the Tekken games is that while every weak attack sounds painful, each heavy blow sounds like an explosion. Naturally, Tekken 6 features great sound design, from the music to the not-so-subtle sound of each landed hit. The Japanese voice acting works fine, as well; I'm not qualified to judge the delivery of lines spoken in another language. Many of those lines are cheesy from a writing standpoint, but the voices that deliver the lines are strong enough to keep from bringing the game down.