Here's a list of every skillshot in Bulletstorm, in order from lowest to highest number of points, listed alphabetically, and in the game's categories.

General I Skillshots:
25: Graffiti: Kick an enemy against a surface to kill him
50: Afterburner: Kill an enemy that's on fire
50: Antidote: Kill an enemy after they've been infected by puffball gas
50: Enviro-mental: Use an environmental explosive to kill one or more enemies
50: Leak: Get a headshot after putting a Nom Parasite on an enemy's head.
50: Nominated: Kill an enemy after putting a Nom Parasite on their head
50: Sausage Fest: Kill an enemy by shooting a hot dog cart
50: Toxic Love: Kill an enemy while you are infected by puffball gas
50: Vertigo: Kill an enemy by throwing them off a high point(i.e., a cliff)
100: Bad Digestion: Feed something explosive to a Fly Trap
100: Exterminator: Kill an entire Electrofly swarm(these are the blue lightning bug like creatures you'll see throughout levels.)
100: Fast Food: Kill an enemy by ramming them with a hot dog cart
100: Feeder: Kill an enemy by feeding them to a Fly Trap
100: Fly Gy: Kill an enemy by sending him into a swarm of Electroflies
100: Heads Up: Put a Nom Parasite on an enemy and then decapitate them(This can easily be accomplished by using the Flailgun)
100: Intoxicated: Kill an enemy while drunk on Nom Juice(these are the beer bottles you'll see scattered around certain areas)
100: Killer News: Kill an enemy by shooting a Newsbot
100: Pricked: Kill an enemy by throwing them into a cactus
100: Scarecrow: Impale an enemy after putting a Nom Parasite on their head
100: Shocker: Kill an enemy by throwing them into an electrical source
100: Voodoo Doll: Kill an enemy by throwing them into a spiky metal object

General II Skillshots:

25: Bombshell: Kill at least two enemies by exploding a Flailbomber
50: Assplosion: Kill a Burnout by shooting his “ass growth”(the tumor-like bulb on his rear)
50: Discharged: While a Heavy Echo is charging his PMC, kill him with your own charged PMC shot
50: Flyswatter: Smash an enemy against a ceiling using the Thumper
50: Friendly Fire: Kill an enemy by flinging them into the line of another enemy’s fire
50: Full Throttle: Use bullets to kill two or more enemies without letting go of the trigger
50: Gotcha: Leash a Creep or Skull Flaregunner and kill them in midair
50: Parashoot: Leash an enemy out of a gyrocopter and kill him before he lands.
50: Slam Dunk: Use the Thumper to smash an airborne enemy into the ground
50: Trap Shooting: Use bullets to kill an enemy that has been launched into the air by the Thumper
100: Blind Fire: While blinded by a flare, kill an enemy.
100: Fertilizer: Explode at least two enemies that have been Thumped using environmental explosives
100: First In, Last Out: Get an enemy airborne, kill a different enemy, then kill the airborne before he lands
100: Flak: Use an indirect explosion to kill a gyrocopter
100: Stomach Pump: Kill a miniboss by firing a charged drill into his stomach and then kicking him
100: Touchdown: Kill a miniboss by Thumping him
250: Bossed: Kill a miniboss
250: Kick Off: Remove a miniboss’s  helmet, and when he’s stunned, kick his head off
250: Whiplash: Remove a miniboss’s helmet, and when he’s stunned, use your leash to yank his head off

Secret:

25: Ejeculated: Eject a Heavy Echo out of the Jumpship
50: Dino-sore: Shoot the Hekaton’s weak point
50: Fish Food: Fling an enemy into piranha infested waters
50: Kill-o-Watt: Throw an enemy into an electrical building inside the Terror Dome
50: Mass Extinction: While controlling the Mechaton, step on an enemy
50: Outburst: Fling an enemy into the gamma storm
50: Pancake: Flatten an enemy using a barricade in the Skull Hideout
50: Tenderizer: Use the elevator in the Collapsed Building to kill an enemy
100: Ding Dong: In the Collapsed Building, use your leash to open a door and let the rubble crush an enemy
100: Floater: Fling an enemy into water on top of the dam
100: Forced: Fling a Heavy Echo into the electromagnetic pulse barrier that appears when doing the Ejeculated Skillshot on the jumpship. Alternatively, fling a Burnout into the pulse barriers on the Ulysses wreckage.
100: Grinder: Fling an enemy into the grinder on top of the dam
100: Halloween: Fling an enemy into an electrical hazard while he has a Nom Parasite attached to his head.
100: Man Toast: While inside the dam, fling an enemy into a burner
100: Steady Hand: Kill a Burnout with a targeted one shot
100: Sucker: Fling an enemy into a fan
1250: Grilled Meat: Push a Muta-Burnout into the electrical wiring
1250: Minced Meat: Push a Muta-Burnout into the helicopter’s blades
1750: Weed Killer: Defeat the Hyper-Mutated-Flytrap

Anarchy(Online):

25: Yoink: Leash and kill an enemy that a teammate has kicked or slid into.
50: Blood Bath: Toss an enemy into the juicer in the Turbine level
50: Blood Fountain: Send an enemy into the river in the Waterworks level
50: Double Penetration: Kill an enemy with your teammate by simultaneously shooting him with bullets
50: Fish Chow: Send an enemy into the waterfall in the Junkyard level
50: Flattery: Knock an enemy into an elevator shaft, Leash the elevator down on him in the Grand Central level.
50: Ground Chuck: Fling an enemy into the grinder in the Power Plant level
50: Heat Wave: Simultaneously shoot a charged PMC shot at a miniboss with your teammate
50: Man Crush: Crush an enemy using the smasher in the Junkyard level
50: Meatspin: Push an enemy into the revolving door in the Grand Central level
50: Midnight Express: Kill an enemy by flinging them into the monorail’s path in the Grand Central level
50: Nom Nom Nom: Feed an enemy to the dinosaur skull in the Dead Rock level
50: Not In Kansas: Kick an enemy into the tornado in the Dead Rock level
50: Royal Flush: Flush an enemy down the water tubes in the Waterworks level
50: Savior: Kill an enemy that is in melee range of a teammate
50: Tug-O-War: Simultaneously leash an enemy with your teammate
100: Blood Symphony: Kill enemies to fill your Blood Symphony bar and then kill an enemy while in Blood Symphony mode
150: Make a Wish: Fling an enemy into the electrical fountain in the Grand Central level

Peacemaker Carbine(PMC):
*Please note that all of the non-charged skillshots can be obtained with any weapon in the game*
25: Boned: Charge the PMC and shoot an enemy within a moment of sighting them
25: Bullet Kick: Kick an enemy and shoot him to death in mid-air
25: Bullet Slide: Slide into an enemy and shoot him to death in mid-air
25: Headshot: Shoot an enemy in the head
50: Gag Reflex: Kill an enemy with a shot to the throat
50: Overkill: Charge the PMC and shoot an enemy in the head
50: Rear Entry: Kill an enemy by shooting him in the ass
50: Trip Wire: Shoot a running enemy in the legs and finish him off on the ground
100: Mercy: Shoot an enemy in the balls, then kick or shoot off his head
100: X-Ray: Charge the PMC and kill two or more enemies with a single shot

Screamer:
25: One Hit Wonder: Execute an enemy using a single bullet
25: Surgeon: Kill an enemy by shooting a limb repeatedly
50: Enlightenment: Shoot an enemy in the head with a charge shot, and let the flare explode
50: Fast Draw: Kill an enemy the moment they’re in your sights
50: Fireball: Shoot an enemy with a charge shot so it explodes and kills another enemy
50: Fireworks: Shoot a charge shot an enemy that is at least 20 meters in the air
50: Snapshot: Kill an airborne enemy the moment he is in your sights
100: Firefighter: Shoot a charge shot at three or more enemies and kill them while they burn
100: Gunslinger: Score two or more Fast Draw or Snapshot skillshots in a row

Flailgun:
25: Gang Bang: Kill two or more enemies with a single flail explosion
25: Grenade Gag: Wrap the flail around an enemy’s head and explode it
25: Minefield: Kill an enemy by exploding a flail wrapped around a surface
50: Chain Reaction: Slice two or more enemies in half using a charged flail shot
50: Meat Slicer: Slice an enemy in half while wrapping the flail around an object
50: Sadist: Wrap a flail around an enemy, but kill him before it explodes
100: French Revolution: Decapitate two or more enemies with a charged flail shot
100: Head Slicer: Decapitate an enemy after wrapping the flail around an object
100: Homie Missle: Use an airborne flail-wrapped enemy to kill another enemy
100: Smart Mine: Use a flail-wrapped standing enemy to kill an airborne enemy

Boneduster:
25: Burn: Vaporize two or more enemies with a charge shot
25: Legless: Blow the legs off an enemy
25: Topless: Blast away the top half of an enemy
50: Acid Rain: Vaporize two or more enemies in the air with a charge shot
50: Pump Action: Get an enemy airborne then shotgun blast him into an environmental hazard
50: Splatterpunk: Kill a downed enemy by blasting him against the floor
50: Slugfest: Kill two or more enemies with one standard shot
100: Juggler: Blast an airborne enemy twice then kill him before or on landing
100: Piledriver: Get an enemy airborne then smash him into a surface with the shotgun blast

Headhunter:
25: Show Off: Kill an enemy from ten meters without using the scope
50: Accident: Shoot an enemy and have him die from hitting an environmental hazard
50: Bluff: Kill an enemy who is not actually the chosen target of the bullet
50: Broken Wings: Kill a thumped enemy with the guided bullet
50: Letterbomb: Explode two or more enemies using a single charge shot
50: Nutcracker: Kill an enemy by guiding a bullet into his balls
50: Premature: Explode the charge shot to kill an enemy before the bullet hits him
100: Early Retirement: Kill an enemy controlled with the charged bullet before it explodes
100: Hot Shot: Kill a dodging enemy by targeting a weak spot like the head or throat
100: Shrapnel: Explode two or more airborne enemies using a single charge shot

Bouncer:
25: Direct Hit: Kill an enemy with a direct hit from the cannonball
25: Money Shot: Kill an enemy by launching a ball at them and exploding it before it hits anything
50: Boom: Kill two or more enemies with one cannonball
50: Bully: Detonate a cannonball to kill an enemy just after knocking them over with it
50: Carpet Bombing: Bounce a cannonball at least two times before killing an enemy with it
50: Kick of Doom: Kill an enemy by kicking a charged cannonball
50: Trickshot: Kill an enemy with a cannonball bounced off a wall or obstacle
100: Lucky Shot: Kill an enemy with a cannonball that travelled over 100 meters without bouncing
100: Meat Fountain: Kill two or more airborne enemies with cannonball
100: Sledgehammer: Kill three or more enemies with one charged cannonball

Penetrator:
25: Break Dance: Drill an enemy into the ground
50: Fan-Tastic: Drill an enemy into the ceiling
50: Mile High Club: Send an enemy into the sky
50: Root Canal: Insert a drill into an enemy's head
50: Twisted: Fire a drill into an enemy but have him die through other means
100: Airstrike: Impale a thumped enemy into a standing enemy
100: Drilldo: Ram two or more enemies during a slide with the charged Penetrator
100: Shishkebab: Impale two or more enemies with a single drill
100: Stinger: Ram into an enemy with the charged Penetrator, suspend him in mid-air, then kick him into another enemy
100: Wingmen: Impale two or more airborne enemies with a single drill