So I've gone around on the web, trying to figure out exactly how D&D works, and still I'm befuddled. Let me first start by stating what exactly it is I'm trying to achieve.
So, I'm an aspiring video game developer. I'm a big fan of games like Final Fantasy (especially the classics), Persona, Chrono Trigger, etc. Basically, I'm a sucker for narrative-driven games that end in a giant climax with the final boss, whom you must beat to save the world. I'm currently in the planning stages of developing my own game that follows a similar narrative structure, which drew me to D&D.
You see, I've already got a bare bones story created.
The heroes and villains have been developed and fleshed out, the overarching plot has been established, and the setting has more or less been set in stone. Naturally, since the narrative component of my hypothetical video game is where 90% of my focus is going to be, I want it to be as engaging as possible. I'm trying to create an epic tale that wows the player at every twist. However, I've run into what people call "writer's block", and I'm having a lot of trouble getting my characters from the call to action to the climax. If I'm trying to write an epic tale, then I should have a ton of trials and tribulations to fill in that massive blank between the call to action and the climax.
What I have learned about D&D is that the DM can create scenarios on the fly, like when a player takes an unexpected action, the DM must react accordingly. I see this as an opportunity to answer questions about my characters' journey that I otherwise would not have asked myself, thus overcoming writer's block and the story basically writes itself at that point.
My question is:
How feasible is this? I basically want to use D&D to not only have fun with a bunch of my friends, but I also want to use it as a tool to flesh out my own world and give it life. The thing is, my question probably sounds stupid, because I don't know the exact parameters that D&D operates within. For example, I don't know how customizable the setting, classes, and races are. My story is not set in classical high fantasy like D&D apparently is, so I don't know to what extent the foundation of D&D can be redefined to suit my needs. I'm perfectly content with keeping the gameplay mechanics of D&D the same, as I'm mostly focusing on story first and gameplay mechanics second. I'd love to hear your thoughts about this.