Unity is the 'big leagues.' It's not a game; it's the engine that powers the games your kids already love, like Hollow Knight or Cuphead. If your kid is serious about making games—not just playing them—this is the gold standard. It’s a professional tool, which means it’s complex, persistence-heavy, and doesn’t have the 'kiddie' guardrails of a platform like Scratch.
The real win here isn't just a finished game; it's the C# programming and vector math they’ll absorb along the way. Just be aware that the Asset Store is an open marketplace where they might see mature-rated 3D models (think horror or realistic military gear). It’s a space for creators, not a playground.


