A proficient Unity developer must have strong programming skills in C#, along with a deep understanding of Unity’s features and functionality. They should be experienced in game mechanics, animations, and physics, ensuring the creation of seamless gameplay. Key skills include optimizing performance across multiple platforms, debugging, and efficiently integrating 3D/2D assets. Additionally, knowledge of game design principles, VR/AR development, and familiarity with version control systems like Git are essential. These skills ensure the successful delivery of high-quality, interactive, and immersive gaming experiences.