Sean Penn is a great actor, one of the giants in his profession, but he sure isn't Liam Neeson. That's the No. 1 lesson to take away from "The Gunman," his supremely lackluster teaming up with "Taken" director Pierre Morel in an ostensible bid to produce a Neeson-esque B-grade action picture.

There's just something off about the whole movie, which uncomfortably blends a social conscience and a message about African exploitation with the requisite revenge-oriented theatrics. The film wants to have it both ways, telling a story with real-world resonance while it simultaneously indulges in the flights-of-fancy that one expects from genre schlock, including a big battle in a bullfighting ring. The feeble approach shortchanges both elements, producing an insipid muddle.

Penn plays a mercenary sniper named Jim "Twink" Terrier, who assassinates a Congolese governmental figure and, stricken with guilt, spends the ensuing years working for a charity in the country. Some time later, he's sucked back in to the action when he's targeted for elimination.

The credentials are there -- the picture co-stars Javier Bardem, Mark Rylance, Idris Elba and Ray Winstone -- and the story allows for a globe-trotting entrepreneurial spirit as Terrier hunts down those who are hunting for him. Morel knows how to appropriately stage a gritty action scene; his star never seems to be having much fun performing his stunts here, but he gets through them commendably.

The movie teases us by appearing to have figured itself out before slipping back into evoking guilt on Terrier's part and a rightful sense of outrage at the corporate exploitation of Africa that just feels completely wrong when it's expressed here.

The self-seriousness is way out of touch with the realities of the production. This is a fundamentally stupid movie about a muscular superman beating and shooting the living hell out of all those who would cross him. It's not an apologia for continental destruction. It's not a grand conspiracy thriller, though the story takes a turn in that direction.

Neeson, and the other iconic practitioners of this genre, understand how to give genuine three-dimensional performances with just a touch of self-awareness. They get that these movies are supposed to be fun, not social statements, as any sincere ideas are inevitably lost. Penn seems to think he's making an Oscar contender.