Requirements of the Game Project

This is the requirements I've been working on for the game projects. I tried following a Waterfall software development approach, but unsure if I'm doing it right. I tend not to care very much if I'm not doing it EXACTLY right because I mainly do this for fun. 

Requirements 1.0

What purpose does the game serve ?

        Be entertaining to a technical degree

What graphical content is expected ?

        Sprite and Pixel art textures.

        Sprites with different phases to represent movement.

        Top down perspective at about 70 degrees

What audio content is expected ?

        An 8-Bit music track.
        Ambiance tracks, combat tracks, indoor tracks. 


What amount of content is to be expected ?
        Have at least 30 minutes of content.
        Single storyline
        Immersive story


What kind of interactions will be possible with the world?
        Conversation with multible options
        Turn by turn combat
        Inventory system


These are the expected things I hope to fulfill with my game. I might not be able to get everything working but I will update the post to add or remove items as I go. Next in line is the Design part.