When a xenomorph spots you, the hive is stirred and they go into hunt mode, homing in on your location. Your squad will automatically shoot to keep the creatures at bay, but that alone is rarely enough to buy Dark And Darker Gold stop them. Hitting spacebar opens up a more elaborate skill menu. Suppressive fire will slow encroaching aliens in a wide cone, while grenades and shotgun blasts are useful for eliminating specific threats. But using these skills costs Command Points, and by default you only have a pool of three. They regenerate automatically, but the rate is slow.
Hence, Dark Descent's tactical fundamentals involve deploying these abilities effectively, knowing when to stick and when to twist. Yet no matter how well you fend off the xenomorphs, there will be lingering consequences to the fight. Every attack increases alien aggressiveness, represented by a creeping ticker in the top right of the screen. When this shifts up a gear, not only will more aliens prowl the mission area, they'll also send a massive horde in your direction.
But these attacks also increase your squad's stress levels, making them shoot more wildly and consume more ammo. They can reduce stress by popping Naproleve pills cheap Darker Gold, or welding the doors of a room shut for a quick rest. But both consume vital resources.