When shooting weapons, especially big caliber ones and in full auto mode, the player character aim goes up:

I assume this is some gamey thing that guns go up, similar to counter strike, but it makes no sense why the aim gradually goes up when shooting.
Makes no sense and does not provide any benefit to gameplay or gun feel.

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+ FPS bug

• The amount of screen shake is different at different frame rates
  • Screen shakes more at higher FPS
• The amount that the weapon goes up is different at different frame rates
  • weapon goes up more at lower FPS