What Would a Protagonist Have to Do to Instantly Reach the Credits?

[Moonface]

Indiana Jones and the Raiders of the Lost Ark
Indy just doesn't bother to go after the ark and the Nazis end up still dying anyway as soon as they get the ark and open it.

Crash Bandicoot 2
Coco: "Crash can you get me an extra battery?"
Crash: Continues to sleep or just goes any other way than the one that goes to the teleporter, or makes Coco get it who isn't of use to Cortex for collecting crystals.

[Karo]

Kingdom Hearts 1:
Don't build the raft and really Sora, Riku, and Kairi really have no reason to be on the island the night that the game begins. XD

[Moonface]

Dying Light
If no one was to rescue you in the opening, you'd be dead before even getting to take control of your character, which is funny since it means the protagonist doesn't have to do anything different; they just have to not be saved by anyone.

[ShiraNoMai]

Yoshi's Island:

Yoshi sees the baby, the map, fall out of the sky and onto the ground in front of him, and thinks, "Mmm.. well, not my problem!" And walks away back to his Island mates. Mario dies a lonely and terrifying death and Luigi never learns of his brother's existence, if he makes it alive after being captured by Kamek and Bowser.

[Nightingale]

Pokemon Yellow:

Don't wander into the tall grass where all the monsters are, you dumb kid.

[ShiraNoMai]

Paper Mario (64):
Mario defeats Bowser in the first fight against him in Peach's castle, and he falls out of the castle instead of Mario. Kammy flies after Bowser. The castle is now permanently floating above Toad Town. Mario wins, but does he really?

[Mr EliteL]

Damn, that's a good one.

Luigi's Mansion:

Luigi doesn't accept winning a mansion, realising he didn't enter any contest to win something, doesn't call Mario about meeting him at the mansion, so they do whatever they do on a typical not saving anyone or anything day. Which seeing as how Luigi would call Mario originally, Mario was at Peach's castle or wandering around in...Toad Town I guess?

[ShiraNoMai]

I imagine Professor E. Gadd eventually gets sniffed out by King Boo and possibly terminated then, which would make Super Mario Sunshine a continuity problem considering he wouldn't be alive to make F.L.U.D.D. Man, now let's see what happens with that...

Super Mario Sunshine:
Mario does not receive F.L.U.D.D. to help him clean up the island. He tries to clean the island up by hand but ultimately comes up short and is then promptly permanently jailed on Isle Delfino, with Princess Peach now Bowser Jr.'s new mama.

[Moonface]

Dead Space
Isaac actually watches the video to the end and realizes that his girlfriend is dead before the game begins, and therefore doesn't bother to go to the Ishimura to look for her.

[Karo]

For FFXIV the Warrior of light just has to kill Thancred and ta-dah!

[Maniakkid25]

Dark Chronicle:
Just keep sleeping lol. He'll miss the circus show, and never get caught up in the madness that is time travel shenanigans.

[Moonface]

As far as I know this is the fastest speed run of any game ever and probably the quickest canonical way a protagonist has reached the credits.

[Mr EliteL]

What I want to know is when did he accuse incorrectly? Unless there was an allowed cut for a restart, or the game automatically assumes a guess was made at the beginning. Dang though, by having only three players take part in the game is one way to knock the time right down. Then it's just a matter of spam clicking to get it right first time.

[Maniakkid25]

Probably a restart. Clue famously has one of, if not THE fastest speedrun on record (under normal settings), because you can just immediately end the game by making an accusation, and hope it's correct. Personally, I don't think those speedruns are as entertaining as, say, Baten Kaitos 100%, because that requires a minimum of 336 hours to complete because of a single item required to 100% the game taking that long to evolve to the form you need. And yes, this exists!

Speaking of which:

Baten Kaitos: Don't go into the Forbidden Forest! Kalas doesn't get caught up in the Malpercio plot, and can go about his life, eventually working up the ability to kill Giacomo like he dreamed of!

[Moonface]

Rayman 2
Globox doesn't get the silver lum from Ly before he gets captured, resulting in Rayman being unable to free them both from their cell at the start of the game. Unable to leave and fight back, the pirates eventually enslave the entire planet and achieve whatever their goal is that I don't actually remember off hand. XD