Story: Most of the anime isn't connected, it works as stand alone episodes, a sort of monster-of-the-week feel to it. It's barely related to the video game series, mostly only the characters and the setting
Animation: Pretty smooth, follows the style of the game aka fast moves very stylized visuals and effects.
Sound: What you'd expect, some guitars and the occational sick lick
Characters: Possibly the best part of the series. Having played all games (1-4 at this point in time) I am familiar with the characters so it is nice to see them all again. Most aren't around for that long. It's primarily Dante and this annoy new little girl who's quite the blemish on the series.
Overall: Only watch it if you're a big fan of the series, a BIG fan. The story structure doesn't have much going for it, the stand alone episodes work against it (as they usually do) This anime is lacking purpose and real interest.