Take Alice in Wonderland and twist it up with a dark theme? Well, this movie or Pandora Hearts is what you might end up with. Both have a Gothic art style and the characters have similar personalities. A lot of work went into the art work too.
It may be a different demographic (Pandora Hearts is shounen), but they have many similar aspects. The hero is a young, naive but stubborn teenager, both worlds contain references to Lewis Carroll's "Alice in Wonderland", and are not shy with the bloody violence. Not to mention the many number of bishounen characters... It's different from HnKnA because it is more action/adventure-based, and obviously it's not reverse harem. I think you would enjoy it if you enjoyed this!
Both series have a creepy twist on something that is supposed to have fairy tale endings. In other words, it takes the normal fairy tale and takes it back to the time of Grimm rather then the Disney fairy tale many of us know.
Both are alternative versions of Alice in Wonderland. HNKNA centers in harem/romance while Kyousougiga is a crazy random journey centered in adventure/supernatural/comedy. In both, the main girl who is transported to another world is voiced by the same voice actress. We also have twins and the White rabbit in both.