Polygon has published a guide explaining how players can unlock the underground tunnel network in the video game Big Walk, which allows faster travel across the map without having to climb hills and mountains. The tunnels appear as coloured entrances embedded in the terrain but remain inactive until players complete a specific in-game task, making this an important early milestone for smoother navigation.

To activate the tunnels, players must complete the yellow tower in the map's northern region, reachable either on foot or via the green tower's ski lift. This involves collecting five red gourd-shaped items and placing them in compartments atop the tower, then using the resulting key at five keyholes around the base before reaching a hidden yellow tunnel entrance near the black tower. Inserting the key there opens every tunnel entrance across the map; each is dark inside but supplies a flashlight, and the tunnels also contain hidden extras worth exploring.