Base

Your Base - Protect it, once destroyed the game is lost.

Tips

 * This is your most important building. Protect it at all costs, as if it is destroyed, the game is over.
 * Put Walls directly around it for a little defense in case boss zombies break through.
 * Make sure to upgrade this often to get better Crystal Mines, and vice versa.
 * You may not need to build Cannon Towers in the first 1-2 nights as it deals a considerable amount of damage at that stage.
 * When upgraded, allows access to new and more buildings. However, you do not need to immediately place everything down when you unlock it.
 * When choosing a spot to place your base choose a spot that has a lot of resources, especially crystal mines, as it will be beneficial in the early game.

Trivia
 initial reference
 * The base actually does quite a lot of damage, however, its fire rate is very slow.