Finish Level 1

Finish Levels 1-5

Finish Levels 1-10

Finish Levels 1-15

Finish Levels 1-20

Build your first defensive tower

Finish a level with less than 10% health on your last city

Have 100 or more missiles in your stockpile

Build 5 more more towers of the same kind in one level

Finish a level with no shield on the last city

Finish a level without killing a single enemy ship

Finish a level protecting 2 cities from be destroyed

Finish a level with no tower build

Destroying an enemy ship by hand with missiles

Finish a level with no damage done to towers or city

Finishing a level out of missiles and not able to buy more

Hit two missiles with one missile of your own

Hit three missiles with one missile of your own

Hit four missiles with one missile of your own

Hit five missiles with one missile of your own