The Final Station is a new sidescrolling shooter that focuses on defeating zombies and inventory management. As you make you way through the game, you need to collect all the ammo you can because you will inevitably run out.
As you work your way through The Final Station, you will be given some additional weapons, on top of the basic pistol you have from the start. You will get access to the shotgun and the machine gun but, as is the case with a number of mechanics in the game, it isn’t made clear how to change between them.
It is just as simple as in other shooters, but it is an unusual button. To change weapon, all you need to do is press the right shoulder button (R1/RB). Pressing the button repeatedly will cycle through the weapons at your disposal. Since using different weapons on different enemies helps you traverse the area more successfully, it is important to know how to switch between the items in your arsenal.
That should help you take out all those annoying zombies with ease in The Final Station. You should no longer be struggling to run past every single one without any ammunition for your shotgun.