Best

Sub-Zero Head Rip (MK) - Simple, brutal, revolutionary. Loved it.

Sub-Zero Freeze and Torso Kick (MKD) - Lengthy and brutal. Uses his powers to freeze the legs of the opponent and as they helplessly crawl away AFTER he shatters their legs, he stomps on their chest - thus, forcing their head to explode.

Kung Lao Vertical Hat Slice (MK2) - Gruesome and original. I love how the bones stick out of the two body halves. Any fatality that requires its own sprite is worthy (for the most part)

Quan Chi Leg Beat (MK4) - Very brutal and somewhat disturbing. The fact that he doesn't stop beating the victim creates a more violent atmosphere. This is probably one of the few things I liked from MK4.

Shang Tsung Soul Steal (MK2) - Original and straight to the point. The decayed carcass that is left behind after the soul steal is *superb*

Reptile Acid Bath (UMK3) - Probably one of the very few fatalities I actually enjoyed in MK3-MKT. It's very original and the victim's body crumples into a gooey mess. This was a great fatality in comparison to the cartoony, explosive-heavy fatalities presented in MK3-MKT.

Kung Lao Ground Saw (MK9) - Again, original and outright brutal. The relatively slow slicing, the blood, the aftermath of Kung Lao presenting the two halves... it all combines to make a gruesome, painful fatality.

Noob Saibot Body Split (MK9) - Noob Saibot has NEVER had a good fatality. This makes up for all of his previous imitation/lazy fatalities combined! It's brutal, original, and gruesome - the 3 necessary components to a MK fatality.

Worst

Jax Giant Stomp (MK3) - Why does he turn into the giant in the first place?

Quan Chi Neck Stretch (MKDA) - Simply lame and boring. It's pretty ironic that a character with one of the most brutal, original fatalities(IMO) ends up having a lame, half assed fatality.

Human Smoke Teleport Decap (MKT) - LAZY, nuff' said

Raiden Electrocution Suicide (MKD) - OK, first of all, this is just pure laziness. It's simply a repeat of his fist MKD fatality (electrocutes opponent until they explode), yet they decided to just add a finishing touch and have Raiden explode as well. No creativity here.

Rain Uppercut (MKT) - Uppercuts opponent, which splits them apart and has them fall on their head and they remain intact? Super lazy/lame.

Kabal Head Inflation (MK3) Simply stupid. He inflates their head by sticking a tube into their stomach, which causes their head to inflate, the body to rise, and then explode? Who thought of this? haha

Raiden Staff Electrocution (MK4) Argh, boring! Nuff' said.

Reiko Torso Kick (MK4) Not only was it copied by Goro and Noob Saibot, but it was super lame and I hated the fact that the arms and head spun around in the air for a bit.

Bo' Rai Cho Fart (MKD) Comedic, but unnecessary. I watch comedy movies and cartoons to laugh at, not MK.
Any of the copy-cat fatalities (Noob Saibot via MK4, Jarek heart rip, etc.) LAZY


OK, I'm done! Seriously though, the MK Team has developed many creative,bloody and brutal fatalities (especially in MK/MK2/MKDA/MKD/MK9.). They were too cartoonish in MK3-MKT and they were too "awkward" in MK4 (hey, I know, they were new to the 3D capabilities).

Best :
Quan Chi's Leg Beatdown
Reiko's/Goro's Super Kick
Mileena's Neck Bite (MKD)
Sonya's Leg Split (MK4...I actually like the replay)
Smoke's World Explosion (silly, but fun)
Kenshi's Telekinetic Tear
Sub-Zero's Decap
Scorpion's Toasty!
Tanya's Neck-Breaker
Hotaru's Body Slam
Ermac's Telekinetic Slam
Kenshi's Katana Bisection
Johnny Cage's Torso Rip (MK4)

Worst:
Quan Chi's Neck Stretch
Frost's Ice Kick (so boring!!!)
Jax's Foot Stomp
Mavado's Grapple Slide
Kano's Organ Removal (MK:DA)
ALL Bo Rai' Cho's fatalities
Li Mei's Super Kick
Mileena's Nail Spit (so stupid!!)

I really dislike a great deal of MK:DA's fatalities. They were mostly slow, with long awkward pauses, and stupid results.

Best:

Shinnok's hand squish (MK4)
Sonya's flaming kiss (MK1-MK3)
All MK2's Shang Tsung's fatalities
Kenshi's telekinetic limb-breakage (MKDA)
Ermac's telekinetic slam-crush (UMK3 & MKD)
Sektor's squishing device (MK3-MK4 Gold)
Kung Lao's when he embeds his hat into the opponent's forehead, then pimp-ass walks towards his lying body and gets his hat to pop back with a chest-stomp on the opponent.
Rain's upside-down uppercut... (illogical and stupidish, I know, but among the most original in UMK3 nonetheless)


Worst:
Both MK3 Liu Kang's meditation (especially the flipper one, as if they deliberately planned to poke fun at Eastern monks' spiritual activities).
Both Stryker's fatalities (MK3)
Cyrax self-explosion in MK3 (just how on earth does he fight the next character in the arcade bar, if he practically killed himself!?)
Smoke's Earth destruction (MK3) (illogical and exaggerated, as well as almost totally uninventive).
Kano's skeleton rip (MK3) (I'd otherwise manage to like it, if it weren't for the idiocy of opponent staying on ground while Kano rips his skeleton with ONE hand)
Jade's bone scattering with her staff (UMK3) (illogical and moronically executed, plus might not Jade be just a little too weak to succeed at that?)
Both classic Smoke's fatalities (UMK3).


And, well, there are more, but guess these come to my head most clearly.

Best:

01. Kung Lao's Hat Slice
02. Sub-Zero's Spine Rip
03. Liu Kang's Dragon Morph
04. Scorpion's Toasty
05. Kitana's Kiss of Death
06. Quan Chi's Leg Beat
07. Reiko's Big Kick
08. Shang Tsung's Soul Steal
09. Sektor's Trash Compactor
10. Sonya's Kiss of Death


Worst:

01. Quan Chi's Neck Stretch
02. Jax's Growing Man
03. Raiden's Caddle Prodd
04. Tanya's Neckbreaker
05. Liu Kang's MK1 Arcade Drop
06. Kabal's Ghost Scream
07. Reiko's Shuriken Toss
08. Classic Sub-Zero's Screen Goes Black
09. Smoke's Blow Up The World
10. Kenshi's eyeball pop

Best Raiden: MK1 head explosion, MK4 body explosion, MKDA Body explosion Sonya: MK3 purple bubble, MK4 Splits, Kung Lao: MK2 Split, MK2011 Split Liu Kang: MK2 Dragon, MK4 Dragon Reptile: MK2 Head eat, MK3 Acid Puke, MK4 Face eat, MKDA Acid and Eat Kitana: MK2 both fatalities Mileena: MK2 Both fatalities, MKD Head rip off, MK2011 Be Mine Quan Chi: MK4 Leg Beatdown Kai: MK4 Body rip Johnny Cage: MK1 Head knockoff, MK2 all 3 fatalities, MK2011 Head and body knockoff Baraka: MK2 Impale Sub-Zero: MK3 Body freeze and break, MKUltimate3 Icicle Impale, MKDA Spine Rip, MKD Ice freeze and decapitation Shang Tsung: MK2 Soul Steal, Kintaro Morph, MK3 Soul Steal, Bed of Spikes, MKDA Soul Pound Tanya: MK4 Both fatalities Fujin: Tornado and explode Jax: MK2 Both fatalities, MK3 Slice, MK4 Arm rip Scorpion: MK2 Toasty, MK3 Hand from Hell, MK4 Both Fatalities, MKD Limb dismeble and head snap, MKvsDC Drag and push up from Hell, MK2011 Torso and head split Kano: MK3 Laser Eye, Skeleton Rip Cyrax: MK3 Both fatalities, MKDA Slam and Explode Sektor: MK3 Compacter, MK2011 Missle and Destroy Sindel: MK3 Scream, MKD Scream Stryker: MK3 Taser Sheeva: MK3 Skin Rip Kabal: Head Explode Hotarou: MKD Head Twist Noob: MK2011 Body Rip <3 Jade: MK3 Uppercut & Impale, MKD Headcabob Bo Rai Cho: MKDA Body Jump, MKD Fart Fatality Kira: MKD Feet stab and body rip Shinnok: MK4 Both Fatalities Worst Liu Kang: MK 1/2 Uppercut, MKD Both Fatalities Scorpion: MKD Head Rip (COMPLETE rip off of Sub-Zero!) Dariou: MKD Both Suck Tanya: MKD Both Suck Raiden: MK4 Staff, MKD: Both Sucked Baraka: MKD Head knockoff (Pretty dull.) Kung Lao: MK3 Whirwind Kabal: MK2011 Split and decapitation (Sorry, just like the MKD fatality... LAME.) Quan Chi: MK4 fatality steal... no creativity. Kai: MK4 Head decapitation MKA: Create a Fatality.... L-A-M-E. :(