Soukou Kihei Votoms: The Last Red Shoulder
Released in 1985, this OVA tells a critical part of the story between the TV show's Uoodo and Kummen arcs. Although the TV series covered the Red Shoulders in some detail, we didn't get to see much of Chirico's time there or the people involved, and we get both of those here.
(Source: mahq.net)