You can play with mouse & keyboard :

Arrows or ZQSD to move ( it is a French configuration so change the input in the launcher if you need )

Mouse to aim 

Left click to shoot

R or Right Click to retry

Or you can play with a Gamepad :

Left stick to move

Right sitck to aim and shoot ( this is for Xbox 360 Controller, you may need to configure the HorizontalR and VerticalR Input  with your joystick in the launcher )

RB/R1 to retry