NEON STACK is a collection of 5 playable protocols from the N-CARTS universe — logic and reflex challenges with their own visual and audio identity. Designed as a lightweight, replayable autonomous digital cartridge. The entire game is a single self-contained HTML file (native CSS + JavaScript, no libraries, 100% offline with no fetch, <66 KB, 10×18 canvas, synthetic Web Audio API audio and local hi-score). Compatible with keyboard, mouse and touch on mobile, tablet and PC, with 5 OSTs and 5 animated backgrounds — one per protocol — and ready for BSV on-chain cartridge.