Only the Airlock is pre-built (already dug) on the 4th surface bay (left→right). Dig/build on the five bays to the right of the airlock (no dig left of the vault door). Dig connected rock for Raw ore, crush it into spendable Ore, then place rooms. Mission Control needs Vault Lv10, 5 crew at Lv20, and a mix of rare ores (copper, gold, titanium, diamonds). Security unlocks at Vault Lv25. Vault Level also gates dig depth & defense.

How to play: Rooms cost a recipe of Regolith ◆ plus metals & gems (Cu, Ti, Au, Moonstone, Diamond). Rock you can dig right now shows its density tier and contents on hover (or long-press); rock further out stays unknown until you dig up to it. Two-step expansion: tap connected rock to DIG (yields Raw + chance rares) → then Build (+) to place a room on the cleared bay. Airlock vault door = come/go (click) / upgrade select (double-click) — on the 4th surface bay (left→right); dig/build only to the right of the airlock (no Dig Ore / Build left of the vault door). Surface strip (G) is 9 bays (blank rock ×3 | airlock | dig/build ×5); floors below are full 9 bays — pack three 1×3 rooms and you may leave no elevator shaft. Production, Crusher & dorms merge up to 3 wide. Staff a Crusher to refine Raw → spendable Regolith. Elevators dig deeper (dig bay first, then place shaft). The last empty bay on a level can only be an elevator. Drag crew onto rooms (2 stationed per bay). Dorms: 5 beds × width × room level. EVA for Ore plus rare haul (copper, gold, titanium, diamonds).

Collect: tap / right-click a glowing room to pull power, O₂, water, food, or crusher Ore into your bars (Fallout Shelter style).

Controls — mouse: right-click to act · left-drag to pan · double-click a room to zoom (Esc / wheel / double-click to exit) · Shift+right-click a room to recall crew. Touch: tap to act · drag anywhere to pan · double-tap a room to zoom · pinch to zoom. HUD: ☰ = vault menu (operations, save & exit) · ⬢ = materials · ☺ = crew · ＋ = build.