The Spirit of the Beehive since it focus, among other things, on the outcome without hammering it home.
Also Pan's Labyrinth and The Devils Backbone.
Those are, mainly, post-war. We have many good post-war movies but about Civil War there are few good ones.
Some good movies about Spanish Civil War could be "Land and Freedom" and La Vaquilla.
There are some tragic stories with books that directors don't dare to make yet. Gernika or La desbandá.
By chance, it's filming a movie about Gernika right now.