I am an experienced game developer, I use Unity a lot, I'm good for this job, I can use either Monodevelop within unity or Visual Studios, Not that it makes any difference, just showing I can work to your requirements, I think the hardest would be to update the API, changing obsolete lines of code etc etc, The main I ask is that the Project Fee is paid upfront, Its a risk prevention technique that helps stop us freelancers worrying about losing money when we accept a project, for example my bid is $140 and freelancer have added $15 to that, that will be taken from me when I click accept, I prefer employers that are willing to extinguish that payment upfront. That way I don't lose out if you try to refuse payment later on and if there is to be a dispute. Don't get me wrong, I want to trust my employer but due to bad experience on this website, Its better to ask for this upfront. Freelancer.com also recommend we do this. Send me a message lets talk.