If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
You’re the commander of a mercenary group on a distant planet. Your mission is simple, defend your territory against 30 waves of attacks from space creatures. Purchase new weapons, hire more mercenaries, buy new perks and evolve your fortress to fulfill this task.
Arrow keys or W,AS D keys to move.
Mouse to aim and shot (Hold the mouse button to keep firing).
1-0 to change weapons.