I have just watched Ivan's Childhood. As you all know, I am no reviewer, so I'll just give you a few of my thoughts.
This movie, in black and white, has some of the most poetic images I've seen (and you know Tarkovsky does give us many, many moments of these poetic images in his films.)
It seems to me that the film is a contrast between a young boy's innocence with that of his being a scout in the war. The former is beautiful youth, happiness, nature. There is a scene where he "flies" over a landscape to join his mother (shades of Andrei Roublev) and his laughter is beautiful and rings true.
Contrast that with his trudging through a swamp filled with birch trees, covered in mud, as a young scout in the war. His parent's are now dead.
There are dreams - light and playful, and some I don't understand. Some of his dreams seem to take place in the war. There is one introduced by the dripping of water and shows Ivan and his mother looking into a well that is at first full of water and then the angle changes as he looks into an empty well.
There are images of an old windmill, a dead tree, a strange old man, and of dead soldiers hanging by their necks from a limb over the water.
Something about this young scout who seems to be almost in charge of some of the soldiers, reminds me of "Empire of the Sun" - though Tarkovsky's film is much darker.
I am left not knowing a lot or understanding everything, but I am left with poetry and images and yes, sadness. The ending is bleak and the screen goes black, but I know I have been in the presence of an artist (Tarkovsky.)
I hope you have seen this or that you will see it, and really review it here. By the way, the young Ivan in this film, is the bell ringer at the end of Andrei Roublev.