I cant really say I was disappointed by the Jonah Hex movie, because I had low expectations going in. But they certainly did a thorough job of ruining a good story. (Spoilers follow, if it matters.)
At least they picked the right story to tell the excellent Quentin Turnbull arc from the early Weird Western Tales days. They even (mostly) abandoned their earlier plans to combine the Turnbull arc with a zombie story. But then they got rid of just about everything that made the Turnbull story interesting, and replaced it with a mass of clichés.
In the original story, Hex was framed for betraying his comrades and killing Turnbulls son; in the movie, he actually did it (and it all happens offscreen, thus weakening its dramatic impact) but its presented as justified (as anti-terrorism, what else?). In the original story, Turnbull is pursuing Hex for revenge; in the movie, Turnbull has already taken revenge (by scarring Hexs face and killing his family things he wasnt responsible for in the comics) and its Hex whos out for counter-revenge. Nor was Turnbull originally a James-Bond-style supervillain with plans to blow up Washington DC with glowing orange torpedoes launched from a scarlet steampunk submarine; he was just a bitter old man whod lost his son. The original story featured both Union and Confederate villainy; the movie ramps up the Confederate villainy and erases the Union villainy. And unlike the comics, the movie never shows us the affection that Jonah Hex and Quentin Turnbull originally felt for each other. In short, most of the moral complexity of the original story is ironed out, along with most of the drama.
In general the movie seems unsure how to handle Hexs Confederate past. In the comics, Hex had found himself unwilling to fight any longer for the Confederacy (primarily because of the slavery issue), but also unwilling to turn his former comrades over to Union forces; thats apparently not anti-Confederate enough by contemporary Hollywood standards (Civil War movies nowadays tend to whitewash the Union, just as in the old days they tended to whitewash the Confederacy), so, as I mentioned, the movie actually has Hex betray them and shoot his best friend (though, strangely, for reasons that have nothing to do with slavery). Moreover, the chief plot concerns Hexs protecting the Federal capital from an attack by unreconstructed Confederates. But the movie also has Hex, in dialogue, say that he rejects both the Confederate and Union causes as hypocritical. Were further told that Hex never favoured secession, yet the rebel anthem that plays over the closing credits suggests the opposite. Its as though the script had been co-authored by a Union apologist, a Confederate apologist, and a curse-on-both-your-houses Hummelite. Well, something for everyone, I guess. (Interestingly, the Confederate villains never give a clue as to what they were fighting for; they say nothing about slavery, secession, or anything else. Instead, theyre depicted as being motivated by pure ungrounded hatred of America.)
Moreover: in the comics, although Hexs adventures occasionally included supernatural or science-fiction elements, they werent the norm (apart from what Ive elsewhere called Phases III and IV, both relatively brief), and Hex himself was certainly never portrayed as possessing supernatural powers. Seeing Hex raising the dead and Turnbull wielding a futuristic super-weapon (or indeed Hex himself wielding slightly futuristic weapons) was jarring. And whats up with all the crows, and the constant reversion to the red-tinged astral plane or whatever it was? The movie keeps focusing on these as if theyre going to be important, but they turn out not to be and are never explained.
Between the high-tech doomsday weaponry, Megan Fox running around pointlessly in her underwear, and originally complex antagonists transformed into simplistic over-the-top moustache-twirling Confederate-flag-waving megalomaniacal psychos with bad Southern accidents, I kept having unpleasant flashbacks to watching the 1999 Wild Wild West movie desecrating yet another childhood favourite though this movie wasnt as bad as that one. (The recent Sherlock Holmes movie, though much better than either mess, had similar problems.)
As for casting: Josh Brolin didnt quite capture Hex for me (the character was inspired by Clint Eastwoods westerns, and its hard for me to see anyone but Eastwood in the role) but he actually did a decent job. The rest of the cast didnt do so well (apart from Michael Fassbender, who was fun to watch as a psychotic Irish assassin). John Malkovich basically just walked through his part; but its hard to blame him, as the character of Turnbull was made into a cardboard villain, leaving Malkovich very little to work with. (Id love to see Malkovich tackle the role of the original Turnbull.) As Id feared (here and here), Megan Fox as Lilah was blah; and her passing mention that her real name was Tallulah Black no doubt intended as a nod to the fans was really closer to being an insult to the fans. In the comics, Tallulah Black is the female equivalent of Hex himself: hard-bitten, cold-blooded, cynical, vengeful, massively scarred, and missing an eye. Well, Hollywood isnt going to go for a massively scarred Megan Fox, and as for the rest, Fox is not exactly the ideal actress for that sort of thing; Angelina Jolie would be a better choice. (For the original Quentin Turnbull arc, see Showcase Presents Jonah Hex; for the first appearance of Tallulah Black, see Jonah Hex: Origins.)
A couple of other gripes: for a movie about a character so obviously inspired by the spaghetti westerns, it rarely makes an attempt to look interesting. Contrast the unforgettable opening scenes of The Good, the Bad, and the Ugly or Once Upon a Time in the West with … well, Ive already forgotten the opening scene of Jonah Hex. The spaghetti westerns also knew how to build suspense with pauses and silence, while Jonah Hex has A.D.D. pacing, evidently subscribing to the view a popular one in Hollywood that nothing builds excitement like a relentless, nonstop barrage of bigger and bigger explosions. Also, youd never guess that Jonah Hex is any kind of western at all, for there are no distinctively western landscapes; in fact most of the action takes place in the southeast, and the one scene that I guess is supposed to be in the west is a giant sandpit that is apparently someones idea of what a southwestern desert looks like.
In addition: voiceover narration is a very tricky thing; it can be done well, but it seldom is, and narration from a character whos supposed to be somewhat mysterious and remote, like Hex, is an especially bad idea. (Would The Good, the Bad, and the Ugly be improved by narration from Eastwoods character?)
Finally: for a movie that features not only Ulysses Grant but also the White House, the Capitol Building, and an under-construction Washington Monument, the disclaimer at the end that all persons and buildings were fictional was an appropriately risible and bogus ending to a risible and bogus film.