What does the player do moment by moment?

The character is presented with a Quest by a Quest giver. Complete the quest to earn the reward.
Looting is the primary way the character earns enough credits and upgrades to survive through to the next mission.
Rewards are the end game of questing. Earn enough rewards, the character grows stronger and more capable.
Player Progression is the way a Player Character gets stronger and more capable. Each mission completed, enemy killed, location discovered, or loot box opened, earns the character an amount of experience (XP).