Add new features to existing Spritekit-Swift iOS game

I am looking to have an experienced iOS developer(or team) work on adding new features to an existing iOS game. The game is written in Sprite Kit + UIKit + Swift. I will be providing all the needed graphics/design work needed for implementing the needed functionality, so this work is about programming alone and not creating artwork. The requirements for this job are : 1) A person or team who has the ability to program in Xcode with Swift/UIKit/Sprite Kit. 2) I am only looking for experienced elance individuals or teams. 3) You should speak english fluently. I cannot give too much information about the game publicly. I will let you know of the details if I become interested in your proposal. This project will be starting off with adding some simple game functionality, but I am interested in adding much more down the road and working with you on many other new features. I am looking to establish a good relationship so that we can keep working together on more projects. The deliverables for this job will be the source code and other components that you may have created (although that won't really be required). Please reply with examples of your previous work. This will help me see whether I like your work and I will reply to you with providing more details.