Portrait of Ruin could have utilized the World War 2 backdrop much better. Have a cold, methodical, reserved, and all-business SS character named Josef investigating the castle, who is at odds with an impassioned, and rugged American agent with a five o'clock shadow named Jim Campbell who has somewhat of a footloose demeanor even though he takes his duties seriously, The dynamic could be somewhat like how Graham and Yoko and St. Germain and Zead were enemies.
EDIT:
Also, somehow manage a boss fight against Josef while he's within a German Tiger tank. He should also have some secret highly advanced Nazi weapons for fighting on foot.
While I would've loved a more WWII/Hitler occult connection, the idea I did do a rough draft of in my own story(I don't know if you guys remember my origin story regarding Graf Orlok being a knight who goes against his king after his family is left to die of the plague, I called the story "Mitternacht"). There was various entries in it(pretty much modeled after CV, as you have various lineages battling Orlok and his minions throughout history). My WWII entry(which was written as a response to PoR's falling short) featured, oddly enough, a character by the name of Jesse Campbell, a pilot flying a group of soldiers to Romania after word that one of Hitler's occult divisions, Dämmerung, is in the area. He discovers that Dämmerung(a team that consists of Friedrich Ganz, the cold ruthless leader; Lillian Mueller, hailing from a lineage of mystics that once had ties to Orlok centuries ago; Hans Schiller, unholy scientist nicknamed the "Totenkopf" and said to be one of Mengele's mentors; and Kurt Hauser, a young sociopath who is also a brilliant strategist), is setting their sights on Mitternacht, castle of Graf Orlok, in hopes of tapping into his dark power to aid the Third Reich's cause. In that little story, Jesse teams up with a female companion, Elise Bertrand(a young, swordwielding French mystic sent by the church to stop Dämmerung and a potential resurrection of Graf Orlok).