Hello , My name is Petrescu Eduard , I am interested about your project couse I am a PHP Developer and I've worked with game engines too ( Unity 3D , GameMaker) ,all the functionality made from scratch both backend and frontend could be donein 7 days ( it will depends on how complex will be the system) , the web design could take up to 7 days too , and all the PHP will be a nice coded OOP very easy to modify in the future . If you want to discuss more please contact me . Thanks