Much fewer people. Extreme intolerance. Hell on Earth.

We'd have to get stoned.

A nightmare.

It's not possible to follow every rule without breaking other rules in any authoritarian religion.

Which religion are you talking about?

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

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.

A big shitshow

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.

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.

We would be living in the dark ages man.

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

First question: Which religion...

It would cease to exist.

Uglier than it is now.

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

We won’t.

Basically, last one in jail wins.

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.

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 which religion!

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.

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

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.