Reviews, writes, and optimizes SpriteKit game code for correctness, modern API usage, performance, and cross-platform compatibility. Use when reading, writing, or reviewing SpriteKit projects. Trigger whenever the user mentions SpriteKit, SKScene, SKNode, SKPhysicsBody, SKAction, SKEmitterNode, SKTileMapNode, GameplayKit (GKEntity, GKStateMachine, GKAgent, etc.), or any SpriteKit/GameplayKit class — even if the request is a simple question about game code, a bug fix, or adding a feature to an existing SpriteKit project.

This skill is open-source and available under the MIT License. See LICENSE for details.