First question: Which religion...

Know your History look at the "dark ages " it will tell you all you need to know lol

Which religion are you talking about?

Christianity
Amish
Hindu
Buddhist
Judaism
Santeria
Shai Islam
Sunni Islam
Taoism
Rastafari
Shinto
Bahai
Paganism, etc.

I think it would end with a nuclear holocaust and cannibalism.

We won’t.

Mosaic Law stated: “Fracture for fracture, eye for eye, tooth for tooth, the same sort of injury he inflicted should be inflicted on him.”​—Leviticus 24:20.

Just imagine how that scenario would work out.

Depends which religion!

Much fewer people. Extreme intolerance. Hell on Earth.

The zombie apocalypse

It would cease to exist.

Perhaps that is what is happening right now here in America.

We'd all be psychopaths trying to do two or more different things at once.

Keep god's laws first over man made laws, but don't forget that god commands you to honor the law of the land you live in.
Love one another, but it's totally cool to have slaves.
Let your light shine so others can see your good works, but don't show everyone you are doing good things or you'll be a hypocrite.
Turn the other cheek, but take up your sword.
Don't kill, unless god tells you to sacrifice your own child.
Don't kill, but wipe out every living person in a specific city if god says.
Don't kill, but kill those who commit adultery, but only throw the first stone if you are without sin yourself.

Basically, last one in jail wins.

The Society of Friends tries to follow the gospels to the letter (and George Fox their founder who was psychotic). They do a pretty good job of it too. Of course there are evangelical Friends who are more baptist than anything else. Nixon was an evangelical Friend, see what that got us.

I don’t think that is possible unless you choose one to follow to the letter.

We'd hack each other to pieces because one man's nectar is another man's poison. People would be condemning each other for supporting abortion/ eating beef, pork/ wearing or not wearing certain kinds of clothing/ exposing a body part/ being gay/ ....the list goes on adding more and more ways to find what's different in each religion instead of recognising that the core of each is love and peace. The reason: Human species is competitive and sees control as a means of survival. So it's impossible for all the people of the world to follow any one religion to the letter.

We would be living in the dark ages man.

Uglier than it is now.

Well - a lot of crime, burned down houses, people drowning at sea, etc each week on the Sabbath, because if the police, fire service, coastguard, etc worked then they would have to be STONED TO DEATH.

What it is now, a shit show crock full of hypocrites!

A big shitshow

Oh, about like the Thirty Years War, magnified a million times!

There would be lots of genocide and slavery. Unruly children would be stoned, and rapist's gets to marry his victim. For more details, just read the OT.

Depends, as said below, on the religion. For the most part - more death and destruction and less liberties. Some of the nativist religions would possibly be more tolerant, but we all know that even if one religion prevailed, scisms would occur.

depends on the religion. Following the Abrahamic religions to the letter would likely lead to a dystopian theocracy where free speech and expression are non existent, poverty, war, and disease are rampant, and slavery of women and foreigners is accepted and celebrated. Meanwhile, following certain pagan religions to the letter would be the exact opposite, and would likely lead to a tribal anarchy where unorthodox and occult practices which the Abrahamic religions condemn would be commonplace. If that doesn't seem compelling, the best way to answer your question is to look to history for examples of what happens when religious literalists have complete and total control over society and government.