Shooting up Helghasts is about to become a co-op affair, with Killzone: Shadow Fall's wave-based multiplayer component, Intercept, launching as DLC on June 25. As a reminder, anyone that owns a season pass has already paid their way for Intercept. If your interest is piqued but you don't own Shadow Fall, you can still wait around for the standalone release of Intercept, which is due later this year.
The related PlayStation Blog post also details Petrusite capsules, which can be returned to the team base in exchange for bonuses like an instant restock on health and ammo. They'll also let you go full Oprah by doling out jetpacks or mini guns to your entire team's load out. You might need it though, as your opposition can call in "special Helghast champions with unique abilities" to make things as difficult as possible.