Amblin'
Before it was the name of his production company, Amblin' was a short film by Spielberg shot on 35 mm. It follows a couple who meet in the desert. Set during the 60s, the two attempt to hitchhike and later become friends (and then, even more...). Eventually, they part ways, but what a story for the ages!
Letters from Iwo Jima
Technically, this is not a Spielberg film, but he did complete some production on the set. The film demonstrates the Japanese soldier's perspective of the legendary Battle of Iwo Jima. It received four Oscar nominations and was highly praised by critics and viewers alike.