Iron Man 

Thanks to Robert Downey Jr.'s charm, Slurpee ads and a surprise colossal 2008 summer mega hit, Marvel comics' durable Iron Man has broken into the top flight of superhero celebrity. Now even the layman on the street is vaguely familiar with old shellhead's résumé: Tony Stark, a cool exec with a heart of steel, was a playboy weapons merchant who turned super-powered altruist after a nasty run-in with terrorists. With a hunk of shrapnel lodged in his chest, Stark was forced to put his tech genius to work keeping his heart beating with a mini reactor that also powers his invincible armored suit. But even if you've got all that down, the follow-up film offers a host of new and returning baddies and allies, all taken from the pages of the comics, and this handy guide should help you chat up the geeks around the water cooler.

Black Widow
Scarlett Johansson

Though she began as a Cold War femme fatale, Natasha Romanov — codenamed Black Widow — has become a heroic fixture and team player. After Emily Blunt had a scheduling conflict, director Jon Favreau tapped Johansson (whose hubby, Ryan Reynolds, is now filming Green Lantern) to play the part of the deadly, kung fu-kicking secret agent. Film lovers will rejoice that filmmakers scrapped her Russian accent, sparing Scarlett the embarrassment of dropped vowels. Meanwhile, fanboys dropped an ocean of drool at the sight of Scar Jo's curves poured into a skintight leather catsuit.   

Nick Fury
Samuel L. Jackson 

In the comics, Nick Fury is the consummate utility player, a cigar-chomping, two-fisted World War II hero amped up on longevity drugs and now director of the global super-spy task force S.H.I.E.L.D. The old dude was so white that Knight Rider's David Hasselhoff once played him in a tragic TV movie. However, when Marvel launched a line of grittier "re-imagined" versions of their core titles, Kick-Ass scribe Mark Millar and artist Bryan Hitch started drawing Fury to look like Jackson; old-school geek that he is, Sam was honored to rock the eyepatch. Look for him in the next few Marvel movies as Nick rounds up recruits for the hush-hush Avengers team, scheduled to get its own flick in 2012.

Justin Hammer
Sam Rockwell

A jealous, temperamental corporate rival to Stark's empire industrialist, Justin Hammer prefers to stay well out of harm's way, instead using his deep pockets to fund the goons who throw down with Iron Man. In the funny books, he's a cagey codger drawn like Peter Cushing, but on screen he's a manic dork, as played by the ever-amusing Sam Rockwell   

War Machine
Don Cheadle 

It's hard here for a sidekick; just ask Terrence Howard, who played Stark's good buddy, pilot and military liaison, James "Rhodey" Rhodes, in the first movie. Howard allegedly asked for more scratch amid rumors of offscreen clashes, so the studio promptly replaced him for the sequel. Don Cheadle nabbed the part, and he also gets all the cool toys: his own suit of armor, tricked-out with missile launchers and other heavy firepower, painted black and dubbed "War Machine" for that extra tinge of badassness.  

Whiplash
Mickey Rourke 

Here's where things get tricky; Ivan Vanko in the comics was just one of many poor schmucks to don the shoddy Soviet Iron Man knockoff armor called "The Crimson Dynamo," which Iron Man used to regularly beat back into plowshares. In the movie, Vanko is the offspring of a disgraced Ruskie scientist defector Anton, who Tony's dad had deported back in the '60s. Now the son uses his own tech skill to modify dad's old blueprints to use against Stark in a multi-generational vendetta. His energy-whip gimmick is borrowed from another villain, an unrelated mob leg breaker, though Rourke's own calloused, circus peanut fingers, tatted torso and swollen forehead are pretty scary weapons on their own.

Corey Hall's writes about film for Metro Times. Send comments to letters@metrotimes.com.