Fun despite all sorts of flaws.
There's just something bizarrely fun about watching Bela Lugosi in the middle of a movie where he is the only element of an old school B&W horror flick in evidence. It's as if he was dropped into a sub-par espionage plot and began picking off the bad guys, one murder at a time.
He's the only really good part to the movie, but he's enough not only to make it worth watching, but to make you giggle about it for hours after the fact.