It's a nice looking movie, but the plot is really lame.

I understand your objection. But watching someone in complete control while toying with their prey isn't all that far fetched -- and that's the only thing I think is happening with the Louis Cyphre-stringing-Harry-along dynamic. Cyphre lost track of Johnny after the deal, finally caught up to him, now wants to enjoy tormenting him before the big reveal. Whether that storyline appeals to you or not is up to you of course, but I think that's the basic idea and I go with it.

The "selling of a soul" is silly -- but that's a well worn theme as well throughout literature and film. So as a work of fiction, the premise works for me. I certainly don't take such a thing as reflecting reality.

There are real problems -- I think -- with the chronology of the characters in the film that others have delved into, and the ritual business that was hastily explain by Ethan Krusemark at the end of the film. But that aside, I ignore the warts and blemishes if it's a film that I really like. And I love this film. For whatever reason.

You’re missing the point - Lucifer wanted to toy with Johnny and have him remember his ‘crime’ before damning him. Simply killing an unwitting amnesiac carries no satisfaction.

On the amnesia, it’s a combination of damaged memory from shell-shock combined with Angel’s soul being dominant within Favourite’s body. It’s not purely a medical problem.

I don’t see why Favourite’s souls would be damned before he sold it. He was clearly a ‘sinner’ to a degree but unlikely one that warranted eternal damnation.

Because Cyphre is evil.

He enjoyed watching Johnny go on a wild goose chase.

He particularly enjoyed it when Johnny finally figured it out.

The entire episode is for Cyphre's amusement. Which makes sense - he got Johnny back for trying to make a fool of him.