• playground rebuilt as a hands-on hacking curriculum: 8 flags across a compromised-box kill chain
• map shows the break-in phase by phase; learn is an 8-module applied-security syllabus
• graduated hint — escalates where → tool → command so nobody gets stuck
• progressive unlock: the box grows as you clear levels
• provable sandbox safety: bwrap-boundary + content selftests
• folded into scenarios as free play; every render fits 79 cols