just need to make a protype first with still photos of characters and the scenes wich you encounter characters (martys fence, basiles yacht, westcocks trailer,)
Each encounter should have around 10 options of how you can interact (eat food with bhank, shoot up roids with bhank, .... Or choose to engage in a fight wich would have an algorthm based on his health your health ,strength ect
No need to have a perfectly polished game but i can easily see the game being very popular $$$ with some basic framework, scanned photos, algorthms