Click on the towers menu (Top left) to choose which tower to place. Placing towers require money which you earn every wave. Click on a placed tower to upgrade it. It also requires money. Click the Start button [>] to start a new wave. Enemy types 1. Red 2. Blue 3. Green 4. Yellow 5. Orange 6. Speedy (Pink) 7. Black 8. White 9. Steel/Grey (Fire/bullet proof) 5 health 10. Blimp (Red) 80 health 11. Zeppelin (Blue) 200 health 12. Airship of Doom (Green) 350 health