I ran a design school for eight years where fourteen-year-olds built real projects—wearable medical devices, robotic systems, public art installations—in two-week studio cycles. No grades, portfolio-based assessment, and a structured constraint I designed that did exactly what the Playdate is doing here.
It was a two-sentence writing assignment. Before you could describe your project, you had to state the idea in one sentence (the soul) and the concrete form in one sentence (the body). Kids who could prototype a working medical device in two weeks couldn't articulate what they'd built. The constraint forced the thinking the tool couldn't.
Jach's argument—"you could impose the same constraints on Unity"—misses the point. You could. Nobody does. The tool shapes the behavior. An engine that can do anything invites you to do everything. Or, for young people, nothing. A 1-bit screen with a crank asks you one question: what's the game? That's not an arbitrary constraint. That's a design decision about where the student's cognitive effort goes.
The expensive tool teaches the tool. The constrained tool teaches the thinking. They're both necessary but they serve different stages, and most programs only do the first one.