I wouldn't include Terraforming on an "underappreciated" list. It's as mediocre as shooters come and, if anything, gets more attention than it deserves because of its high price tag and fancy background visuals (which are actually impressive in only half the stages).
I support the suggestions of Sinistron, Psychosis, and World Class Baseball. How about Tricky Kick as a real dark horse? It's not a masterpiece, but it's a fun and very challenging puzzle game with some entertaining story "cinemas."