12 Split up for extra fun
If you’re playing in co-op with a friend, you don’t have to run into every battle side-by-side. One of you can run off to find a plane, then rain fire from above while the player on the ground sprints around with a shottie. Alternatively, one player can take a position up on a hill or in a tower and provide sniper support for the stealthy player creeping around with a knife in hand. Thinking creatively with two players will give you even more options. And if all else fails, get in a two-seater plane and just shoot stuff.