Kick-Ass was, in the tradition of inferior/offensive Mark Millar comics made into films, pretty good!
I really enjoyed how tactical the action in this film was; every time there was a serious fight (so, basically, a fight involving Hit Girl), Hit Girl's decisions in combat had serious and trackable implications. We start seeing this trend in the warehouse fight in which Hit Girl frees Kick-Ass and Big Daddy. She kills the lights, goes to night vision, and takes out an entire warehouse full of submachine gunners with an M9 and a tactical knife. First off it was cute how they didn't even bother filming Hit Girl for this-they just overlaid Modern Warfare 2 graphics on footage of guys dying in a night vision filter. She drops a few guys with the element of surprise before her enemies switch to spraying and praying, which is a reasonably good tactic under the circumstances, and the suppressive fire actually keeps her in cover and forces her to make an actual tactical decision instead of just doing cool shit or dodging bullets: she throws up a strobe light as a diversion, keeps her back to the wall (heeding Big Daddy's advice from earlier in the movie), and flanks her last two enemies.
Later on Hit Girl has to kill an entire building full of mafiosi. We see her preparing for the fight in her hideout-she loads up on smoke and stun grenades and prepares an H&K MP5, and that's not just me being a dork about weapons I will never use in my life, that part is important from a Chekhov's arsenal perspective because it comes up when she gets overconfident and angry, and starts making mistakes. She kills everyone in the lobby with the silenced M9 (yes, still important), goes upstairs, kills a couple of guys with rope darts, and then takes cover before she confronts a long hallway full of gangsters equipped for CQC-Strikers, UMP's, and pistols for the most part. And this is where she fucks up.
So we've seen her prepare grenades and a SMG. She's in cover. Her enemies don't know where she is. She could very easily cook two grenades off a sec, lob them out, and cornershoot the MP5 on full auto, in all likelihood dropping everyone in the hallway and leaving her with her choice of expensive CQC weapons to use on the final bosses. But she does not do this. Presumably because she is overconfident and angry and has killed everyone in the film so far with the M9 or a blade, she rushes out of cover and attacks with dual M9's, relying on Prince of Persia-style wall runs, acrobatics, and disarms to kill about a dozen better-armed enemies. In the process she goes through what looks like upwards of six clips. The MP5 is nowhere to be seen and the grenades remain present but unused. She winds up with the last guy supine underneath her, her pistol in his face, and no ammunition. She could knife him. She could pistol-whip him. But she's fucked up and she knows it and it's rattled her, presumably, so she runs for cover in a room where she can't flank anymore, and then Kick-Ass has to save her.
It makes for a better ending of the movie, putting her on more even terms with the final boss, who's a much tougher unarmed combatant than the physically weaker Hit Girl, who does better with small weapons and blades. It also shows that Hit Girl isn't a flawless warrior, which is great; it brings the tactical choices she's made throughout the movie full circle. This kind of tactical buildup is just one example of the way Kick-Ass handles dramatic escalation really well in many ways.