The current project.
As of now only the training level and level 1 (out of 5) are available.
If you have a joystick:
Make sure it has at least 8 buttons or you will be forced to use the mouse.
You must now make your button key. It maps whatever buttons are on your joystick to those of a standard controller.
On the command prompt you will be asked to press buttons corresponding to the letters on a standard controller. For example, 'A' would typically be the one that's easiest to press with your right thumb, or the red one in the above image.
If you don't have a joystick:
Then use a mouse.
A: Fire Lasers
B: Barrel Roll
X: Bomb (hold until you want to detonate)
Left-click: Fire Lasers
Right-click: Barrel Roll
Middle-click: Bomb (hold until you want to detonate)
Keyboard buttons: Pause