Well in order to shoot you equip a weapon and simply reload, there is a bullet counter in left corner. I guess I can do a quick update and add some info at the game start or so.
The problem with this is that for the first time player, it's not "equip the gun and simply reload". It's "Figure out that you don't have a gun equipped. Figure out that this game has shooting in it, and guess that it's not simply a game without shooting. Figure out that the I button opens the inventory. Figure out that the C button opens the character screen. Combine that knowledge to equip the gun (the first time I played, I only figured out about the inventory screen, and moved the gun to those four squares at the bottom, which I figured were some sort of weapon quickslots, but it seems like I was mistaken (?). Figure out that the gun takes ammo, and doesn't start with any. Figure out that ammo isn't an item in the inventory, and you can reload without it. Figure out that the R button reloads."
I'm not saying there needs to be an extended tutorial or anything, but a few "here's how you do this" prompts, or, at the very least, a screen that tells you what the controls are (that you can access from both the start screen and the pause menu) are needed.
You can also do things like start the player with a loaded gun already equipped. That way they can jump right into the game and will probably figure out that they can shoot. If, later, they get a second gun, they will be more inclined to figure out how to use it. Also, there should be a sound effect for when you try to shoot when you are out of ammo. Feedback like that is a good way to let the player know that there is something needed of them, as opposed to letting them think that there's just something wrong with the game.
Having now successfully fired the gun, I can now say that bullet effect is really nice looking.
Also, at some point mashing all the keys on the keyboard trying to figure out what keys did things, I opened the Skill Tree, and I'm not sure how to close it. (After again going through every key on the keyboard, I eventually discovered K was the key that opens and closes that window. The window should have an X button like the inventory and character windows)