Move the mouse to aim and click the left button to shoot, click the relevant position around the spaceship to build a defense tower (need to unlock slowly), use skills with the QWE button (need to buy), and switch weapons with the number keys 1-5 (need to buy).
Tips: In the game, weapons and tower defense devices can be purchased and upgraded.
![](//imga3.5054399.com/upload_pic/2013/5/27/4399_15101631838.jpg)