Hi, there - my name is Amin, came from America.
I've read your brief and can see that you'd like to build an endless runner game similar to Temple run in the water slid environment, especially, I've already built an endless runner game before, so that can do provide the high-quality product with awesome design..
Based on analysis of requirement and from my experience, I offer $4500 / 30 days.
Milestone steps:
1st - Game design in PSD format.
2nd - Game front end development based on approved app design.
3rd - Game mechanism core development
4th - Game completion.
Of course, my offer is a bit higher than other freelancer's bid, but when you think about the high-quality product for your successful business, I think it's a correct time and reasonable budget.
I am extremely experienced in iOS and Android Game development with 10 years and I am also very strong at Unity framework, as well as game art design.
If you'd like to take a look at my previous works, please check my freelancer profile.
https://www.freelancer.com/u/aashshak
I will do my best in order to realize your ideas into reality.
Please contact me, I hope to discuss this job more details.
Thanks and best regards, Amin.