The basic operation of the game is using "↑, ↓, ←, →" and "space" on the keyboard.
"←, →": Control character to move left and right in a map.
"↑, ↓": Control weapon's attack angle. There is a dial at the lower left corner to show the angle.
"Space Bar": Control weapon's attack power. The longer the space bar is pressed, the greater
the attack distance is. The length scale at the bottom will show current power.