Hell was always a part of the Bleach universe, it was introduced earlier on in the Bleach manga/anime with the gates of hell being shown but nothing coming of it. Until now when Tite Kubo involved himself in the production of this movie/story.
Starting off like a typical Bleach movie/story, Ichigo and the gang are attacked by mysterious entities and are forced to journey to hell on a rescue mission to save someone dear to them.
Although the explanations are brief, they are effective and none the less a new character explains Hell to Ichigo and the group and what their situation is as 'Sinners' and who the massive beast like things that devour their souls endlessly are.
Hell is a very cold, and lonely/cruel place as you can imagine, there are several layers, and none the less the battles in this movie and worthwhile and as a result of said battles, Soul Society end up being involved to protect the world of the living.
Although I found the movie worthwhile, it's a shame this is all we get of Hell in Bleach, it would of made a fantastic arc, the place is so atmospheric and well creepy.
We even get to see Ichigonator in all his glory.