More action than characterization. The entire plot- and there's nothing to spoil so don't worry- involves Dave (a mercenary) helping a wizard in a raid against would be kidnappers. Actually, more of the most brutal sting operation; raid sounds too much like World of Warcraft.
Oh no, I was wrong! And of course I'm not gonna start dissing on Dave, he's too much of a bad ass. So, after I got that through copious amounts of hair... On my skull... I remembered something great in that story other than the action! My characters aren't as flimsy or wooden as Kristen Stewart. They have what every 80s action fan wants- or even what Hollywood isn't realizing lately.
Remotely interesting characters with flare. Comedy. Spicy, quick dialog. But back to those characters. Harold the Wizard thinks he's a wizard who actually may or may not be a wizard. That's what makes him so great. He's unpredictable and just doesn't give a damn. Dave is the same way.
And then there are the differences. Dave is a more up-close-and-personal killer; he doesn't like using guns that much. Harold however, is an excellent marksman- I mean so is Dave... The wizard thinks he's something supernatural while Dave knows who he is. While hardcore in everything, each of them both have a little heart.
So how does this heart show up? Through dialog. I absolutely hate reading a three page bio on a character in a story. Especially when it's in the middle of an action scene. So I let the characters talk and learn about each other. Along with a few asides through fight scenes; but essentially a quick sentence and then move on.
It's all people really need. As my mom keeps telling me, your overactive imagination will fill out the rest.