There are common used terms:

• Kill'em'All - Defeat all of your opponents by killing them all. Scenario only.
• Mining resources - Collect as much of resources of certain type for the limited time. Scenario and Challenge.
• Quest - Complete a specific task. Scenario and Challenge.

Multyplayer game mode. Gameplay and objective depends on game type. Singleplayer game mode. Gameplay and objective depends on game type.