The story in Chocolate Underground is generally a good story. There were some moments that were cliche, and there were far too many of these moments. I did however like the story of rebelling against the established authority, and making things the way they should be. But the pacing was sporatic throughout the series. In some episodes, there seemed to be little to no plot change, and in other episodes there seems to be large changes in the plot. There were also some points in the plot that were never made clear, or theads were left dangling. Overall, I think that the story was good, but it needed more time to grow and mature.
The art in Chocolate Underground is probably the serie's strong point. The art is rather good, and the animation is smooth. However there are several instances of still crowds, and still backgrounds. These stills took away from the realism in the story. The characters looked good for the most part, although there were times when they looked unreal.
The characters of Chocolate Underground are ok, but they lack development and personality. They seemed to be based on stereotypes, and had few things that made them unique. again this is a series where it's shortness is its downfall, and the characters needed more time to develop for the audience. A lot of the characters seem to be driven by only one thing, and it makes them seem two dimensional and bland. However, There were a few moments where there was some development, and it made things more interesting.
Chocolate Underground is an all around mediocre anime. It isn't the worst filth ever to grace the world of anime, but it isn't something that should be regarded as a great anime. If time is short for you, than this series will please you in some ways. Its an ok anime, certainatly there are better ones out there, but this one deserves at least a small look.