“Blackhat” has the look of a hit. For starters, it’s a thriller directed by Michael Mann (“Heat”, “The Insider”), and audiences usually respond to his movies. They also love Chris Hemsworth, who went beyond his Thor character in 2013’s “Rush” to prove he’s got what it takes to be an A list actor. Here’s a chance to prove it again. There’s also Viola Davis, who’s a terrific actress (which couldn’t hurt). What does hurt about “Blackhat” is that it’s not very good. Hemsworth plays a computer genius. But before we meet him, the movie opens with a RAT infiltrating a Hong Kong computer system that controls a nuclear reactor. The world is at risk (naturally), unless a certain blackhat is stopped. Enter Wang Leehom, who plays a Chinese military man assigned to bring down the cyber-terrorist. But he can’t do it alone, so it’s up to Hemsworth to lend a hand and save the day. Interesting stuff? Perhaps. Sadly, the movie never takes off. Instead, it just sits there like a lump of breeding clichés. The dull script by Morgan Davis Foehl gets no help whatsoever from director Michael Mann, which is a damn shame. Maybe I was expecting too much from Mann and his group of talented actors. But if my calculations are right, “Blackhat” could well be Mann’s weakest movie in years.