I’ve stuck here because there’s a bug. I don’t see any fire knob.
Somebody help 
here is an image
Just click where you want to fire
nothing happens(( I saw on a youtube video that there’s must be a text “fire” on the monitor in the game. But the problem is that I don’t have it. You can see it on a screenshot.
Reload the chapter and try again. For me it was flickering a lot so just try to mash your use key on the screen.
You also have to be fairly close to the screen, IIRC.
I was as close to the screen as possible. Nothing changed. I’ll try to reload the chapter. Hope this would help.
I believe you have to click on the screen, and not push the use key.
Click the screen with your mouse, as if you’re actually using a mouse.
It’s really weird. And it’s not uncommon that the screen gets all screwed up and won’t detect your button presses. If that happens, just keep trying.
What they said, after you’ve put the area where you want it to be, keep pressing your left-mouse button at the bottom center.
Well, I’ve tried everything suggested in this topic. But it’s still only two crosshairs on the screen where I must point the monster and no opportunity to fire.
Tomorrow I’ll reinstall the game. It’s the only chance
For those, who will experience the same problem - reinstalling the game fixes this bug)