Flatline: a plot idea for a future project

[deadsuperhero]

I came up with this idea today, so here goes:

Plot: A boy named Robert gets in a tragic accident of some sort, and he's put in a coma for 10 years. Trapped inside his own mind, Robert must make his way through his dreams if he wants to recover. He must fight to wake up again. He has to go through everything from the most beautiful dreams to the most horrific nightmares. If he fails in the dream world, his heart rate flatlines in the real one, and he dies.
Later in the story, he meets a girl in his dreams, and falls in love with her. However, he has to face the possibility that she's not real.
However, she is. In the end of the story, Robert wakes up. He was in the accident at age 15, and he always pictured himself at that age. He is now 25.
He stumbles into another room in the hostpital, and finds the girl. She's in a coma, just like him. He has to find a way to wake her up, so he gets back in bed, and aids her in her dreams.

The gameplay would somewhat resemble Quest for Glory. You would complete tasks in your dreams to gain points. You could then pull out a medical file for Robert, and see what new skills you have. Eventually, you'll learn how to manipulate your dreams using powers (flying, levitation, telekinesis, chronokinesis, invisibility, etc)
This idea is still very rough, but what do you guys think of it? How can it be improved?