I first heard about this anime through Crunchyroll's announcing of their winter/spring simulcasts, and my interested was piqued. Overall, it's a very good anime, and has the potential to stand out from the others.
Story: The story starts out with the Red Man, as Ganta calls him, massacring his middle school class. Before he disappears, the Red Man embeds a red crystal-like object into Ganta's chest, which promptly disappears. He wakes up in a hospital and is placed on trial, where he is sentenced to death. He tries to flee, but maddened parents of some of the killed students attack him, and a fake video of Ganta admitting to the killing to Tamaki, his lawyer, and telling him that if Tamaki cleared him, he would tell Tamaki where he hid the weapon. Ganta soon finds himself in the twisted amusment-style prison called Deadman Wonderland, hence the title. All very original, and I look forward to the rest of the episodes, but the anime has the risk of being a 'getting framed for a crime I didn't commit and trying to find the real killer' type.
Art: Truly different from most other animes I have seen. The anime has relatively simple characters, with wonderfully detailed settings, contrasting nicely.
Sound: Nothing special. The opening and ending aren't really noteworthy, and sound almost familiar. One good thing about the music is how nicely it keeps the suspense and liveliness of the anime going (During the opening scene of the first episode, Ganta and his two friends are discussing their class trip, but the piano music in the background left me feeling like something was going to happen.)
Character: Very original, especially Shiro and Ganta. All of the characters have their quirks, and exploit them excellently. I'd love to see the back story on many of them, but I'm sure that will happen eventually.
Enjoyment: Very good. Kept me on my toes the entire first episode, not knowing what would happen. Keeps the blood done to a bearable level, and doesn't get into the gore. Looks like it will be a very good anime to watch!