I saw this film at the AFI Film Festival a couple of months ago and it stayed with me since then. This is not your typical war movie, nor is it your typical animated film. I'd say its kind of a cross between Waking Life and Grave of the Fireflies.
The film takes place in the present. The film's director, Ari Folman, comes to the realization that he cannot remember anything from the time he served in the Israeli army during the 1982 Lebanon War. The bulk of the movie are his interviews with his old army friends where he asks them what they remember from that time. Folman tries to see in their memories something in himself that has been missing, deadened, or dulled. Like Waking Life, there is no "plot." The filmmaker prefers a more interview-based film. This is an "idea film," a poetic film, and traditional narrative style takes a back seat.
Like Grave of the Fireflies, the animation in Waltz With Bashir shows the horror of war and its effect on individuals in ways that a live action recreation could never replicate. The film's themes of human memory and its elasticity are served well by this technique. Rather than a soldier escaping death by hiding in the sea, we get the larger-than-life memory of a soldier escaping death that would look too "real" in a live action reenactment.