It never really seemed consistent to me what kind of supernatural entity a ghoul is. I kind of settled on a subtype of ghost that’s more corporeal than a spectre. I looked up the definition and it wasn’t very helpful. “A monstrous humanoid associated with graveyards and consuming human flesh” is broad enough to include zombies, only this is from pre-Islamic Arabia instead of from Haitian Vodou.
In this movie, Boris Karloff comes back from the dead to get revenge on those who wronged him, but I don’t think he eats flesh, just strangles or snaps necks or something. I expect a lot of overwrought tension that comes off as corny today.
Every story has at least two sides. Erwin Rommel fought on the side of the Nazis, and was a major opponent in Patton, but was himself a distinguished military leader with an interesting story to tell. Though how much of it is accurately told here is debatable, as for obvious reasons this movie apparently focuses less on killing Allied soldiers and more on a plot to assassinate Hitler that Rommel may not have actually been involved with. Even less than a decade after the end of the war, that’s as close as the rest of the world wants to come to celebrating a Nazi officer, which they wouldn’t even dream of doing today.