You have to protect the wall and continually upgrade your guns by merging them. But, the waves of chickens never cease in their relentless assault. That means you have to keep your weapons as upgraded as possible at all times, which inevitably becomes quite challenging when you’re several merge levels deep!

Use the shop to buy weapons individually. More cannons become available when you level up. If you’re frantic in your attempt to stop the chickens, you can just mash the cannon button to create more of any type and pray that works. You’ll also want to keep your wall strong and upgrade your defenses in the shop.