Change 1 letter in a video game's name

Killer is Deaf: pretty much the same game but before each mission there is a game of charades where you have to guess who is the contract giver, what is the target, and why you have to kill him/her.
Victor Van: pretty much the same game as Victor Vran but you are a van instead of monster hunter.
Assassins Greed: almost like Assassins Creed but all the missions consist of pickpocketing and the base game is only tutorial, each of the remaining 12 missions is DLC
World of Poo: now this is a shitty game...

Medal Gear Solid - Destroy a bipedal tank made of medals!

Sad Max - Years after the collapse of civilization, the lone man max is the sole survivor of the human race. He spends his remaining time salvaging debris to upgrade his hotrod. The ending is supposed to be a real tear-jerker.

Mad Marx - Communism strategy game set in Austria Island
President Evil.
Dad space
Lunch Club
Tick Cock Island
World of Poo

Learn Fapanese To Survive - Hiragana Battle - Learning the ancient fapanese art is the only way you can survive in this game.

Bass Effect - epic sounds!
Two Words: Epic Edition - because the word epic was not enough
Fap Heroes - a clicker game about, wel...
Dead Stake - the emotional story of a stake's life
Kane & Lunch: Dead Man - poor kane got poisoned while eating pizza
Jurassic Pork - an isle full of adventures and beacon
The Manner Saga - introduction to good manners
Divine Slice of Wife - wel...
The Fat Lady - horror story inside McDonald's

Could go on for ages :D

Hyper Light Grifter - You travel a ruined world, cheating people out of their money.

La Mulan - A game based on the Disney movie Mulan, only it's entirely in French.

Docket League - A sports management type game like Football Manager, only you're running a law firm.

Super Neat Boy - A child with OCD is forced to continually clean his room.

Legend of Grimcock 2 - Become the legendary grim rooster again and fight against evil forces in this new game about the fight between good and evil.

Arming Simulator - You're getting ready...

Deadpoo - the sequel to this crap.

Herbal Space Program: Try to smoke enough high-strength narcotics that you believe yourself to be in another galaxy.

Half Lie 3: A game that is never going to released because, according to Valve, money does not grow in 3s. 😎
Super Mead Boy: A game where precision is the only way to reach your goal as you jump from deadly traps, carrying a bottle of mead to your beloved pirate princess.

Pick-Ass 2 - you did it once. Now it's time to do it again in the sequel of the award winning Pick-Ass.

Stardew Galley - Try to succeed as a cook after you take over your grandfather's job on the USS Stardew

Guilty Bear X2 #Reload - Everybody accused it of being guilty. Now it's time to prove itself innocent by uncovering the great conspiracy behind.

Grim Dan - A game about a marginally depressed guy

Sakura Teach - The game teaches you the complicated PLOT of all the Sakura games.

Inspired by my most played Steam games:

MayDay 2 = Survive lost at sea until rescue arrives!
The Binging of Isaac = Isaac's journey to a food coma
You Have to PIN the Game = The only way to beat this game is to guess its credit card pin number!
Teal Fortress 2 = Can you paint the whole fortress this specific shade of blue before time runs out?
Left 4 Deaf 2 = ...what? I can't hear you...

Failout

ShitLord - speaks for itself

bump

Ultimate ZOOM - Without weapons, or the ability to walk slowly, you must sprint through gauntlets of ever more brutal hordes of Hellspawn as you make your way to the Mars Hellgate and then through the bowels of Hell itself.

Touchlight - Immersive story rich sci-fi adventure with a light-bending mechanic to change others' color perceptions (Torchlight)
Path of Emile - walking simulator with the musings of a pretentious Frenchman. Pretty much a French version of Dear Esther. (Path of Exile)
Remember Fe - periodic table of the elements quiz game (Remember Me)
Firmwatch - Lead a law enforcement agency trying to crack down on crooked lawyers. (Firewatch)
Overlard: Raising Hell: southern cooking simulator (Overlord: Raising Hell)
Lori and the Blind Forest - RPGMaker bundle trash (Ori and the Blind Forest)
Ori and the Bland Forest - bundle trash platformer that rips off Ori and calls it an "homage".
Siberia - point-and-click adventure about searching for a woolly mammoth in Siberia. Oh, wait... (Syberia)
Costume Guest - clothing game for girls (Costume Quest)

Dynasty worriers-

A bunch of married Chinese men are in panic about the state of their families

Romance of the tree Kingdoms-

a war between the Oak, the chestnut and the Dew that lasts nearly 100 years

Sad rats-

A rats struggle with suicidal thoughts in an unforgiving world.

METAL EAR SOLID - Van Gogh returns as a Terminator to kill people.