Just a short review, because I didn't make it past episode two...
Here is an anime series that should have been good: it had pretty artwork, adult themes (not porn, but characters who were grown-ups and not the usual high-schoolers or middle-schoolers), and an interesting premise.
The first episode begins with a teen-aged Taiwanese assassin codenamed "Glass Heart" committing suicide by jumping off a building. That's a pretty gripping start, and then the story jumps forward a year. Glass Heart's triad boss saved her life by stealing an organ donor's heart, but Glass Heart, who was burned out on killing for a living and just wanted to die, stubbornly refuses to awaken from her coma. Meanwhile, the heart donor, a young Japanese woman named Kaori, killed in a car accident, has left behind a grieving widower.
While deep in her coma, Glass Heart sees strange visions of Kaori, which lead her to awaken, kill everyone in the place where she's been held, and then set off on a quest looking for the donor of her replacement heart.
So why didn't it work? Mostly because the writing and characterizations failed to rise above being an assemblage of cliches, and the visuals weren't much better (sprays of randomly-drifting sakura petals to highlight a nostalgic recollection, anyone?)
The "grieving widower," turns out to be a handsome but rather shallow and repulsive lech, who uses his widower status to hit on every attractive woman he encounters. He then heartlessly dumps the women after a one-night stand, because he's really still in love with his dead wife. In-between his brooding monologues (and his detective work to track down the person or organization who stole his dead wife's heart), he hits on his partner, who repeatedly punches, hits, kicks, etc. him in some hideously unfunny slapstick.
The sudden shifts in mood are jarring, and neither of the lead characters is particularly interesting or sympathetic, so I gave up.
Rating: D+