Helldivers 2 got a new trailer and it outlines how co-op works in the tactical shooter sequel, including new and returning stratagems and friendly fire.

You can equip stratagems to drop resupply caches, powerful weapons, one-time attacks, and helpful aims like a gatling sentry gun. You can also customize your armor, with heavier builds letting you soak up damage and resist elemental attacks, and lighter ones letting you move more quickly and with less chance of enemy detection.

The kind of mission will also affect what loadout you should bring to it. Some enemies are heavily armored, so you'll want to bring armor-piercing weapons and equipment with you. If you are taking out a hive, you should bring explosive loadouts that will let you eliminate multiple enemies quickly and efficiently.