The Dark Knight is so doomy and gloomy, so relentlessly bleak and depressing, so very dark, that it’s tough not to leave the theater feeling a bit down. The large number of explosions aside, it’s not what you typically expect from your average comic book movie, even after the weighty gravity of Batman Begins. Why so serious, indeed.

In many ways, it evokes The Empire Strikes Back, the moody sequel that betters its predecessor in nearly every way. The stakes are higher, the action’s bigger, Katie Holmes isn’t in it … But where it really ups the ante is its villain.

Prior to seeing the film, it’s hard not to roll your eyes at the slavish praise heaped upon Heath Ledger’s portrayal of the Joker. Would the acclaim be so universal had the young actor not died earlier this year from an accidental overdose? But after seeing Ledger’s terrifyingly unpredictable performance, it’s clear the actor’s Brokeback Mountain Oscar nomination was no fluke.

The Joker is a terrorist in John Wayne Gacy makeup; a nihilist with a sense of whimsy. His importance to the movie really can’t be overstated, as it all revolves around his anarchic plans. Begins lacked a worthy adversary and memorable action setpieces, both of which are amply addressed by the Joker. He’s so unpredictable, so brutal, so randomly destructive that tension and anxiety build throughout until you actually begin to question whether Batman can triumph.

This being a superhero movie, of course he does, but rarely has victory felt so hollow. The movie tries to shoehorn in a glimmer of hope when a prison inmate goes all no holds barred on a detonator (thanks, Zeus!), but it’s largely ineffective. Gotham City is still a festering cesspool, several lives are ruined and Batman is more tortured than ever. But perhaps saddest of all, because of Ledger’s untimely end, we’ll never get to see his Joker again.