Stan pulled out his tranq gun from the inside of his coat.  “I got no problem puttin’ you down again, El Creepo.”  He cocked the gun and pulled the trigger. [This is good, clear action]

Marx moved so fast even Louis’s eyes struggled to track him as he threw Sera into the path of the tranquilizer dart. [I think this would have more punch if you split it into two sentences. Longer sentences read faster, but when you’re describing specific action, you may want to clearly identify each movement in its own sentence.] It hit her in the chest and she went down fast.

Fury filled Louis’s mind. “Excuse me, you fuckin’ jerk. That was my girlfriend.”  He charged at Marx, grabbing him by the collar, and launching him twenty-five feet into the side of Shirley’s Tahoe.  All of the windows shattered with the impact and the frame bent inward, as if it had been t-boned by a school bus.  Marx crumpled to the ground in a heap.  Louis ran up and kicked him in the stomach.  “I’ll make you burn, you psychotic syphilis blister.” [This is a strong paragraph overall – very cinematic. I might break up the three-clause sentence ‘He charged at Marx…’]

Marx grabbed his legs and pulled his feet out from underneath him.  Louis went down with a thud but scrabbled away before Marx could leap atop him.  He raced up the street and stopped at the corner to see Marx giving chase.  Louis looked for the first thing he could grab to use as a weapon.  He grasped the pole for the street sign and gave it a yank.  It broke off where it went into the frozen ground. He gave it a twirl over his head like a baton and thrust it at Marx, who soared through the air at him with the guttural yell of a Viking warrior.  The jagged end of the pole connected with Marx’s gut and he flew back in a high arc, landing on the wooden privacy fence that separated the house on the corner of Pearl and Main from what used to be Chagrin Falls’s busiest intersection. [I like everything in this paragraph except the last sentence, which seems too wordy. Otherwise, you’re describing action very well. I can picture it easily.]

Louis ran toward Marx, ready to deal another beating with the pole, perhaps the final one, when Marx hopped to his feet.  A 2-inch plank of fencing protruded from his abdomen.  Though Marx was breathing hard, the wound didn’t slow him down much.  Instead, he yanked the plank out with two heaves, leaving a gaping hole in the bloodless flesh just below his sternum. He launched it at Louis like a supersized dart, where it connected with Louis’s right collarbone, cracking it. [As good as the previous two paragraphs were, this one could use some work. Simplify the action-oriented sentences. If you want to simulate the closeup used in movies, you might throw a descriptive sentence into the middle, perhaps dealing with Louis’s horror at Marx’s wound and his blase reaction to it. That makes the sudden yanking out and hurling much more effective.]

Louis dropped the pole from his numb arm.  He was about to pick it up again with his good one when he heard a metallic gron. [What’s a metallic gron? 🙂 ] He looked up and saw a white compact car hurtling through the air toward him like a giant snowball.  Louis ducked just in time, and the little Ford sailed over his head to crash into the front window of Larry’s Guns, Shoe Repair, and Beef Jerky.  The peal of the shop’s burglar alarm reverberated off the surrounding buildings, summoning cops that could no longer come. Marx stood at the intersection laughing. [Believe it or not, your verbs ending in (-ing) make this paragraph weaker than it would be if you used simple past tense (-ed).] “I’ve got plenty of fight left in me, Louis.  How about you?”  He raised his hand and another car, this one a blue full-size sedan, levitated off the ground and launched itself at Louis.  He didn’t have to duck so much as back up several steps, for the Chrysler didn’t sail nearly as high and as far as the Ford had.  It crashed into the street and tumbled in a spray of broken glass and plastic.  Pieces of the flying shrapnel chewed into Louis’s face and hands.