Ichi the Killer is possibly one of the most incredible dark humoured films in existance, especially considering how little people understand the film even though they've watched it. The first disc is the uncut version of Ichi; the film is basically about Japanese mafia members, sadomasochism and a young lad who can't stop crying called Ichi. If I carry on, I'm sure I'm going to give something away that will spoil the movie, but it's well worth watching it a few times to make sure you know who everyone is, and what's going on. And remember- this is a comedy!
The second disc is a wonderful collection of interviews, backstage and gallery. If you enjoyed the film, you'll probably enjoy all of the featurettes, all of which have subtitles (except one trailer), though don't expect too much of an explanation. That's what the film's for. The same goes for the manga "version". It is not in fact a "version", it's more of a debaucherous and violent hentai movie on the theme of Ichi, akin to the cartoon series the film gets its basis from. Well worth a look.