In retrospect, it's not surprising that the Wachowskis would be the ones at the helm, aided by director Tom Twyker. The six-storyline movie (based on David Mitchell's novel) is a mash of sci-fi, post-apocalyptic primitive future, and mythology... Something that the Wachowskis would be completely at home with. The six different lines are strengthened by having different directors for each story to give them each a different feel.
It's ambitious from the get-go. The book/movie spans six different storylines, six different time periods, and six different genres. Although the book offers these narratives in two separate chunks (going first chronologically with each portion of the story before finishing each story in reverse order), the movie entwines all of the storylines together from the beginning.
Mitchell's novel received its strength by the fact that each story was conveyed differently -- through journal-writing, letters, thriller novel and more. Mitchell shows himself a master of genre-writing, deep characterizations, and playful literary manipulations. Unfortunately, this effect is mostly lost in the movie. In the novel, there was also a play on what was real. Was the sci-fi writing the future? Or just a contrivance? Were the letters meant to be actual documents? This was confused by the appearance of a comet/reincarnation motif that appeared time and again throughout all the narratives, whether they were meant to be fictional or not. Of course, the motif also emphasized that when it came down to it, the whole book is contrived...by David Mitchell.
Cloud Atlas certainly gets points for ambition. Some of the scene transitions are clunky and overcontrived (by the end of the movie, I physically winced every time we got the overused overhead shot of the ship), but some meld together cleverly (I actually loved when one character gave a narration over a montage of all the different stories). On the one hand, I commend the Wachowskis for juggling six stories so well. On the other, I have to admit that if they didn't decide to juggle/switch between stories so much, the bland story-lines would have fallen flat. So I'm not sure whether to be disappointed with the weakness of the stories, or impressed with the visual pyrotechnics offered to keep them afloat and keep the audience engaged.
I was left wanting more in every aspect -- story, acting, clever writing. Cloud Atlas was good...but it could have been great.