Project Clean Earth: How to Beat Chapters 77 and 78 Swarms

To clear Chapters 77 and 78 in Project Clean Earth, switch your build from single-target burst damage to overlapping area-of-effect (AOE) crowd control, piercing projectiles, and continuous perimeter kiting. Chapter 78 features massive rushes of high-health gorilla enemies that move quickly and body-block your movement path. Surviving requires building sustained hazard zones to thin trailing hordes while moving in wide loops to prevent getting pinned against map borders.

Recommended Build Priorities

Dense mob stages render single-target damage ineffective because front-line targets absorb hits while dozens of reinforcements push behind them. Balance persistent area denial, penetrating weapons, and mobility upgrades so your combat frame can maintain spacing.

Priority Type	Target Effects & Weapons	Tactical Purpose
Crowd Control	Freezing effects, shock zones, knockback projectiles	Slows down rushing gorillas and halts flanking attempts
Sustained AOE	Gas clouds, flame ground hazards, spinning blades	Continuously damages compressed clusters trailing behind you
Piercing Damage	Penetrating lasers, beam weapons, railgun-style shots	Cuts through heavy frontline mobs to strike trailing enemies
Mobility & Defense	Movement speed boosts, temporary shields, cooldown reduction	Prevents corner traps and shortens defensive downtime

Prioritize cooldown reduction alongside your damage upgrades. Shorter cooldown intervals ensure ground hazards and defensive barriers stay active constantly, leaving no gaps for fast melee units to reach your character.

Arena Kiting and Corner Avoidance

Standing still in Chapters 77 and 78 guarantees defeat due to dense collision hitboxes. Maintain an active, looping movement path to control where the swarm condenses.

Commit to outer perimeter loops: Run along the outer edges of the map in wide circular orbits. This pathing forces trailing gorillas and support units into a tight line behind you, maximizing the damage of your lingering ground hazards and rear-firing weapons.
Never reverse direction into a tailing pack: Doubling back sweeps you directly into the densest cluster of enemies. Maintain your forward arc unless a path is completely cleared.
Cut inward before corners pinch: Map corners are the most lethal hazard in both stages. If a swarm approaches while you run toward a wall boundary, cut toward the open center of the arena before the corner seals shut. Only push directly through packed enemies if an invulnerability or shield skill is active.

Handling Chapter 78 Gorilla Waves and Performance Spikes

Chapter 77 features mixed projectile pressure alongside moderate swarms, which you can handle with ranged mitigation and steady attrition. Chapter 78 abruptly changes the dynamic by fielding aggressive, high-health gorilla rushes that close distance quickly.

Swap your secondary upgrades in Chapter 78 toward knockback, pure movement speed, and persistent floor hazards. Pushing the frontline backward buys space for piercing beams to shred the pack.

Extreme mob counts in Chapter 78 can also cause frame drops on mobile devices, resulting in input latency during critical turns. To maintain smooth controls during dense spawns:

Lower graphic and particle settings in the game menu before starting the run.
Target freshly spawning clusters immediately to clear sprites before they fan out across the entire screen.
Widen your kiting circles early whenever you notice input delay to avoid collision traps.