The Low-power Tunnel is a side tunnel that branches off of the Main Tunnel, at Level 28, seen from Level 27. It consists of twenty-five levels, and was the first tunnel to introduce and make use of the gameplay mechanic darkness. Two tunnels branch off of the Low-power Tunnel Run 3 Game, the Memory Evaluation at part four, and the New Tunnel at part 15. The Child is also unlocked after beating the Low-power Tunnel.
The Low-power Tunnel was the first tunnel to introduce and use darkness. Darkness is a gameplay mechanic in which some or all tiles in a tunnel run out of power. When tiles run out of power, they blink on and off or dim, and may eventually go dark all together. When they go completely black, the tiles are still there, however, they are much harder to see against the dark background. Occasionally a whole tunnel will run out of power, but more often, most turn black while some stay brightly lit, acting as a kind of guide from one platform of tiles to the next. Also, when a tunnel runs out of power, the music may get quieter (when dimming), start and stop erratically (when blinking), or go completely silent (when off).
And for this tunnel and other levels with darkness, we strongly advise turning your brightness up completely to avoid headaches from being unable to see tiles.
After beating the Low-power Tunnel, the cutscene ‘Candy’ will begin. The Child finds a bag of candy at the end of the Low-power Tunnel, then leaves and the focus changes to the Angel, who was standing behind him. The Angel’s thoughts appear on the screen, showing his frustration at all the dead ends, and waiting for the Runner to lead the group home. This is when he decides that he’s “done with all this,” and soon afterwards he begins recruiting as many of the others to go back home to the Planet with him