Find the game in steam library => Right click the game => click "properties" => click on 'general' tab => then click on "set launch options" and copy/paste:

+set g_fov 90 (for a 90 degree field of view)

+cvaradd pm_nobob -1 (for no head bob when walking / running)

*Be sure to put a space between each command, otherwise it won't work.
Alternatively choose the 2nd command alone and edit FOV (field of view) from within the game. It wasn't originally in the game, but was later added. But remember than not all settings take effect after the game restart (for whatever reasons).

Some say it doesn't work for them, when editing the file. But just in case I'll leave it here.

There is a parameter 'Bob' in multiple places the following INI file:
C:\Users\myusername\Documents\My Games\AlienRage\SinglePlayer\AFEARGame\Config\AFEARPawn.ini
You need the Bulletstorm INI-editor to edit that file:
Download here [games.softpedia.com]

+ Also try to:
Change Bob=0.004 to Bob=0.000 in DefaultPawn.ini

1. Open folder '..\Steam\SteamApps\common\AlienRage\Singleplayer\Engine\Shaders'
2. Move or delete the file 'LensFlareVertexFactory.usf'

If you have questions regarding this guide or just got something to say, leave me a comment below.