DEEP CORE ELEVATOR

Skimmers dive from the surface mouth down the shaft toward the core. Ring stations hold your turret brackets — pick a turret (Z / X / C), click a bracket to build, click a turret to upgrade (U) or sell (V).
Three elevator cars patrol the wall cables. Select one (1/2/3 or click), click a ring station or press W / S to rewire it to that ring.
When the alarm screams on a deep ring, press SPACE to RIDE the car yourself: W/S drive the cable, A/D hop cables, guns fire hot until they overheat.