WELCOME TO THE FORUMS!I was just saying that because it looks like your first fanfic. I'm here to give some constructive criticism, take it or leave it.
Biggest concern: MORE DETAIL
Though it has potential, it has such an incredibly weak description that the whole story is collapsing on it self, three little sentences and a little bit of dialogue is nowhere enough for anything, prologue or not.
In the city of Ronto laid a bar, called the "Crimson Tavern". It was popular for Red Army Soldiers, Philadelphian Rivermen, travelers, scavengers, and explorers.
A man entered a bar, by the name of Mikhail Vladovich, and looked for somewhere to sit.
These three sentences could easily be turned into a paragraph or two. That would allow us, the reader, to get a clear and concise image of what your are trying to convey. For instance
In the city of Ronto laid a bar, called the "Crimson Tavern". It was popular for Red Army Soldiers, Philadelphian Rivermen, travelers, scavengers, and explorers. Today was no exception, one could almost feel how crowded the bar was from just standing outside it. Shouts and curses rang down the streets, echoing against the desolate dirt. It would appear as if the whole town had congregated into the Crimson Tavern, it was a place were businesses transaction usually took place and one could always find stories and gossip if they wanted to.
A man entered a bar, by the name of Mikhail Vladovich, and looked for somewhere to sit. That proved to be a problematic situation, the bar seemed to be overflowing with such a strange mixture of people it almost made you want to laugh, people from all over the country came to Ronto, and if they were in Ronto, then they would bound to end up in the Crimson Tavern.
But luckily, Mikhail was spared the trouble of fighting for a seat.
"Sit down here, son," said a old man. His skin was creased and wrinkled like a weather worn map, but beneath the wrinkles and thinning, gray hair was a burning passion, Mikhail usually associated with the young and fool hardy.
"Hello sirs" said Mikhail
"Hello young man, my name is John," said the older man
"Mikhail," they shook hands and talked for a little bit
"Mikhail, would you like to hear my tales of 'adventure'?" asked John
"I would," said Mikhail
I added the bold, not my best use of descrpitive language, but you can easily see the difference it can make. It adds more to the story, making it an easier read and a better one. Also, I added commas to your dialouge if you noticed, this rule applies when your dictating who says what. It excludes "!" and "?". At any rate, seems like a good set up, keep it up.
Good Luck.