Find all the secrets in the human levels.
Finding these unlocks unique gameplay modifiers and secret features (like the Moon Boots or Viva Granata), which you can toggle in the level select menu right below the difficulty settings. Some of these can legit help you like Vampirism get heals on kills. These are only located in the Human missions and there are 2 per mission.
If you prefer a Video guide this series can be helpful
Credit: Gaming With Josie
Mission 1: Basic Training
- Secret 1 [Extreme Tag]: From the start, head to the right side of the main obstacle course. You’ll find this one sitting on the ground near the military camp tents setup along the outer perimeter wall.
- Secret 2 [Moon Boots]: Look for the tall sniper/scout tower that connects to the zipline. Head over to the small tent right next to it, jump up onto its roof, and then do a big jump onto the concrete pillar platform to grab it.
Mission 2: Operation Payback
- Secret 1 [Bloody Mess]: When you are moving through the canyon passes to hunt down the Flak Bugs, keep an eye out for a detour path that leads to an isolated rocky ledge overlooking the valley. The secret is sitting right on the edge.
- Secret 2 [Quiet Hell]: This one only becomes accessible *after* you have completed all the main objectives on the map. Before jumping into the M7 Razorback vehicle for extraction, check the dark, rocky recess right behind the broken fence line near the final defensive gate.
Mission 3: Operation Razorwire
- Secret 1 [Gun Game]: Right at the very start of the level, hug the right-hand rock wall immediately. Follow it along the map edge until you locate a hidden cave opening. Go inside to find the secret.
- Secret 2 [Floor's Not Lava]: Deep inside the cave systems near the final objective, watch for a branching pathway. Take a sharp right turn and then an immediate left down a dark, seemingly empty dead end. The secret is hidden at the back next to the collectible *Laser Training Rifle*.
Mission 4: Operation Obsidian
- Secret 1 [All Out War]: Located at the first outpost closest to where you initially drop into the mission. Look up at the middle tower in the center of the base. You need to climb the adjacent walkway, jump onto the roof of the nearest military hut, and then jump across to grab the ledge of the tower where the secret is resting.
- Secret 2 [No Medic]: From that same starting outpost, hang a hard left and follow the natural cliffside path all the way down until it opens up into a beach/resort area. Search the shallow water directly along the base of that cliff wall to find it.
Mission 5: Operation Tourniquet
- Secret 1 [Birthday Party]: As you approach the massive bridge structure, look at the buildings directly ahead of you (keeping the bridge on your right). Enter the main structure, mantle up the interior broken walls to reach the upper floor rafters, and the secret is sitting in the corner room.
- Secret 2 [Oooft]: Later in the mission when you enter the large stadium to turn on the loudspeakers, head over to **Section C**. A Warrior Bug will burst out of a wall panel here. Kill it, then go into the newly opened maintenance door with the distinct gold trim around the frame to find a hidden birthday party room setup.
Mission 6: Operation Morpheus (Kick the Nest)
- Secret 1 [Viva Granata]: Right before entering the final boss arena to fight the Brain Bug, you will cross a large metal bridge. Stop right at the edge of the arena entrance where the health and ammo crates are. Face the boss room, look over the railing to your right, and jump down onto the hidden ledge below. Walk past the decorative fire prompt to find it in the corner.
- Secret 2 [Vampirism]: Located deep within the lower hive tunnels midway through the mission. In the cavern chamber filled with glowing organic pods, look for an upper rock shelf that requires a series of precise parkour jumps to scale. The secret is tucked neatly behind a cluster of bug eggs.
Mission 7: Operation Seeker
Secret 1 [Super Sonic]: Literally right as soon as you spawn into the level, turn your camera completely around 180 degrees. Walk behind your dropship and look down over the edge of the cliff. Jump down onto the small, narrow rocky ledge directly below the landing zone to grab it.
Secret 2 [Ticking Time Bomb]: Progress through the map until you reach the primary objective area where you have to destroy the massive Plasma Bugs. Look for the giant industrial treaded machinery tracks on the ground near the base. Follow the tracks into the deep metal trench/groove they sit in to find the secret tucked underneath the main chassis.
Mission 8: Operation Slayer
Secret 1 [Enemy Number One]: Inside the final automated fortress complex, before entering the main control command room, locate the auxiliary server racks on the lower maintenance floor. The secret is hidden on top of the ventilation pipes directly above the servers.
Secret 2 [Big Bugs]: In the final extraction zone where you must hold out against the massive royal guard wave, look toward the collapsed hanger bay doors on the far eastern edge of the arena. Squeeze through the rubble gap on the left side to find the final secret of the campaign.