Penguin's Memory: Shiawase Monogatari

Both are excellent movies that deal with animal main characters who only want peace after their times of serving in the war. They are both very contemplative in their themes and heavily focus on both people and nature. Both are very peaceful movies that have a very strong hold on realism, and both contain surrealistic elements. Would definitely recommend one if you've liked the other! 

Dramatic storytelling with psychological health undertones, a stoic protagonist victim of trauma... All with an artstyle where the characthers are represented with cute animals 

Althrought made differently, both share same, fairly uncommon theme: otherwise cute animals taking part in armed conflict (Bunnies in Cat Shit One, Penguins in Penguin's Memory: Shiawase Monogatari), so there big chance that if you liked one, you´ll like another. While Cat Shit One is more action, Penguin's Memory is more drama.