Your goal in this defense/shooter hybrid that puts you in control of a tower mounted turret is to fend off waves on incoming enemies. Use YOUR MOUSE to aim and fire, and 1-5 NUMBER KEYS or "Q" and "W" KEY to change weapons. Press "E" KEY to activate laser (if bought and charged), use "R" KEY to manually reload your weapon. There is a save file function: however, it is one-time use only, meaning you can't use it to restart on level 30 everytime, but rather to continue playing after you take a break. The game is auto-saved at the end of every wave. Good luck!