I would say Alien since it's not that long, the game is probably best digested in a few continuous playthroughs.

Valkyria Chronicles is a slow burn that slowly accumulates these great moments and themes that play with the World War II concept, as well as the SRPG format which it revolutionized. It's a good idea to play it alongside different games in a rotation.

Haven't played Rune Factory since the original but it sounds like you should just finish it!