It plays in many levels. The depiction of a small group of poor people that tries to enjoy little pleasures once in a while is great, and how it works with the symbolic insignificant triumphs of Unno and Shinza. You can also watch it to take pleasure in looking at narrow streets filled with details and hear raindrops falling from roofs.
Upon (initially unintended) rewatch I'm forced to consider whether this may actually be one of the finest films ever made. I loved it beforehand, but this time Yamanaka's observations on humanity felt even more purified, rich and poetic. The sense of time, place and community is unrivaled, Yamanaka creates a fuming boiling pot of life on the edges of oblivion which never fails to being incredibly moving and profound.
Sadao Yamanaka was 28 years old when he directed this film. He died the following year after having been enlisted in the Japanese army. One can only regret that, for the time being, only "Humanity and Paper Balloons" is available in the DVD standard because this film bears the mark of a talented director.