If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
These blue little men have to defend their territory against the invasion of monsters that want to occupy it. Place little men in the trench and give them weapons and armour, by clicking on these elements. At night you can also use the canon! When your blue little soldiers need something, pop-ups will appear above their heads. Give them what they need as quickly as possible, and try to offer resistance against the enemy as long as you can!