itch.io

Holding down the A and S or left and right click at the same time also works, since this emulates the original arcade triggers.

Hi, for anyone playing it recently:
left and right-clicking OR A and S also functions as the left/right trigger respectively.

If your fingers get tired easily or you're worried about carpel tunnel syndrome, hold down the left AND right click (or A and S together) to do auto fire.

I did notice that the cursor temporarily disappears though (will reappear when you stop auto firing).