1. Opening layout: Use Boomerang Tower 1 to prioritize clearing large areas of obstacles and create space for subsequent tower defense.
2. Firepower upgrade: Place 2 fire bottles in the empty space to increase the attack power against the hot air balloon monster.
3. Space utilization: Next, add 3 joysticks at appropriate locations, and use more fire bottles to form a dense fire network.
4. Defense on both sides: Install lower bubble towers and fire bottles on the left and middle sides 4 to increase multi-angle defense.
5. Defeat them one by one: Finally, concentrate your firepower to destroy the remaining monsters to ensure that 5 complete the challenge and win.
Through these detailed steps, you will easily master the skills to clear the 21st level of The Girl Defending the Four Seas of Carrots. If you need more level guides, please continue to pay attention to our on-site resources. Happy gaming!