Cross-Platform Mobile Game Development

I'm looking for an experienced mobile app developer to create a game for both iOS and Android platforms.

Key Requirements:
- Experience in mobile game development
- Proficiency in Unity or Unreal Engine
- Knowledge of both iOS and Android development environments
- Strong UI/UX design skills
- Ability to implement in-app purchases and ads

Ideal Skills:
- Game design experience
- Strong programming skills (C#, C++, etc.)
- Previous portfolio of successful mobile games

Please share your portfolio and estimated timeline.