By defeating enemies, responding to the mission board, and performing various other actions, you'll be rewarded with SP (Survival Points) that can be used to unlock new skills.
There are a plethora of skills that will upgrade Reid's abilities and give him the edge he needs to increase his odds of survival. Some of these include obtaining more items when gathering, increasing max HP and energy, slowing the drain on the food and water gauges, and much more.
