“In the desolate future, when a carefree and adventurous teenager is suddenly forced from his underground bunker into the world outside, he will have to mature quickly if he is to survive both the wilderness and the rogues that inhabit it.”

As the others have said.

This story sets up a plot where the young man doesn't come out from the underground on his own initiative in quest of a specific objective goal..? He's pushed out? and he's gotta grow up fast if he's going to survive hostile forces.??But "to mature quickly " is?his subjective need -- it doesn't constitute a objective goal.

And " if he is to survive " is only a maintenance goal; he's reacting to a hostile environment .? Well, the main character can start out with only a maintenance goal, but?the plot proper kicks in?when something? happens --an inciting incident -- that galvanizes him to? struggle for??something more than mere survival.? At that point he becomes a protagonist proactively pursuing a?specific objective goal.

Hello,
I suggest you to read this article about a script who shares some similarities with your concept:
http://scriptshadow.net/screenplay-review-monster-problems/

It's the story of a young boy living in a bunker underground who decide to go outside to find a girl but this future world is full of big monsters.

I think that if you can mention an objective reason for the boy to go outside we will have a better understanding of the plot.

And if you can change "the wilderness and the rogues that inhabit it" with something that can give the reader a visual picture of what there will be in the movie, the logline would be more powerful.