I recently wrote a SF story, in complete dialogue between 2 men, with no directional tags or anything else.
Again, I put it up for review and got mixed comments. Some people found that the character's voice was strong, and the dialogue flowed well but like any real conversation, the point meanders so you need to have some sort of persistence when reading.
You also have to make sure that the reader doesn't get confused. Because my story was quite long (4000 words or so), even I got confused who was speaking and that messed everything up. I wouldn't advice writing with more than two characters, and for the love of God, name them early. I did have to use a lot of "name-calling" at points to balance out the reader.
Another important point is the way the story is told. You need to tell the story/plot through dialogue, which in my case came in the past. Again, I added larger chunks of one character talking (almost "narratively") to even out the short dialogue remarks.
I think the hardest part is to make the dialogue flow well enough, and create a strong character from dialogue alone since you can't have any description. In my story there was some repetition, and "As you know..." which was inevitable.
It's well worth it though, and it's different.
NB: If anyone would like to read it, or something then just message or whatever: Here's an excerpt... Might not be any good but hey, who knows....
"Anyway I was smoking; the goddamn wind kept blowing the stupid fag out. But bar that, the pier was quiet. Nothing on the radio. Nothing whatsoever. God. Joe, it was quiet- so quiet. I could hear the smoke running away from me. Just like that."
"Bet you could."
"It was so quiet. Like the quiet in death, so there I was smoking and then the rumble. Still nothing on the radio. I even checked, dead quiet 'cept from some lousy weather broadcast--"
"So there was something?"
"Nah. Nothing but silence. Calm it said. Horribly calm. I could see, in the waters. By the dock the waves crashed feebly. Crash. Crash. Again and again. Breaking with no energy. Then the low tide--"
"You checked the manual? Scouted? Measured? Anything--"
"I know the bloody rules Joe!"
"Just saying."
"Yeah well I needed to smoke."
"Fair enough."
"I swear there was nothing. So I carried on. You know Terrip, during the autumn. No clouds. No rain. Nothing. That's why I went; to escape the rain and the cold and wet back here. Worked for a bit. Then guess what?"
"What Sam. What now?"
"Too dry. Yeah, Janice wasn't so happy that I wanted to move again... Nothing was happening. And then it came. Out of nowhere. The screaming."
"From the radios?"
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