Read instructions: Important Arrow keys for grey guy. W, a, s, d for white guy. Black line kills you. Press p key once which brings up shop for player 2. That stops all. Press q key once which brings up shop for player1. That stops all. To exit out of shop, just click the green flag. Before you buy a gun, you need to click the flag and then the number to buy it. After you buy a gun you need to click the flag again to enable the gun to work. If you want to go back to another gun you unfortunately have to pay the amount of the other gun. So get your cash before switching back!
Got help from a tutorial. Here is the link: https://www.youtube.com/watch?v=-W-dADorGOk
