We all swooned at “Collateral”’s twinkling skyscrapers and fluorescent freeways, but “Heat” is Michael Mann’s most gushing LA love letter – a grimy genre flick glossed up to the status of grand urban opera. The director is often accused of trowelling on style-slap at the expense of soul and substance but that grump doesn’t apply here. “Heat” isn’t only his peerless lesson in how to make clusters of concrete and glass look beautiful, it’s also an eloquent study of loyalty, commitment and good guy/bad guy duality. Based on real-life characters relayed to Mann by Chicago cop buddies, Nail McCauley (Robert De Niro) is the fastidious chief of an armed ...  Read the complete review