In order to get unlimited fps you have to modify a file which is located in:
-->My Documents>Amnesia>Pig>, so now you have to open "main_settings.cfg"
and look for: LimitFPS="true"

then change it to: LimitFPS="false"

Note: The maximun FPS that you are going to have match with the current hz of your screen, so If you have a 120hz monitor, set it on 120hz and then start the game, so you will have UP TO 120fps.

↓↓↓ IMPORTANT ↓↓↓

Note: IF YOU HAVEN'T GOT A 120hz monitor and you want more than 60fps you have to change this parameter: UpdatesPerSec="60.000000"

If you want to change your fov, you have to go to this folder:
C:\Program Files (x86)\Steam\SteamApps\common\Machine for Pigs\config

Then open the file: game.cfg and look for FOV = "70", then you can change it to whatever you want, but I don't recommend going further than 80 or 85, so if you want,
change it to FOV = "75"

So just download file, copy "soft_oal.dll" on the game folder, launch game launcher and in the sound option tab there is a new Unsuported device and just start the game.

DOWNLOAD LINK: http://community.pcgamingwiki.com/files/file/7-openal-soft
Source: http://pcgamingwiki.com/wiki/Amnesia:_A_Machine_for_Pigs#Surround_sound

↓↓Please Read↓↓

Originally posted by pcgamingwiki.com:

- Game is using old implementation of a sound system which limits output only to stereo.

Download OpenAL Soft from our repository, our forums or source website.
Extract archive, navigate to Win32 folder from this archive.
Locate file soft_oal.dll and copy it to the game folder (..\Steam\steamapps\common\Machine for Pigs\ for example).

Launch game launcher and navigate to the Sound options tab.
There should be new Unsuported device. Select it and launch the game.

Note: It works but I think it disappears when it Saves game.

Tutorial Source: http://cs2bus.com/sharedfiles/filedetails/?id=177376909

So go to My Documents>Amnesia>Pig>(YOURUSERNAME)> Locate your lastest Save (see the date), then open it with notepad (or Notepad++ (Recomended).

Then locate this: name="mbFogActive" val="true"

And change it to: name="mbFogActive" val="false"

- Apparently there are more than one: name="mbFogActive" val="true" BUT You only have to Change THE FIRST ONE
______________

So you can download this FXAA Injector, just drag the content of the DirectX 9 folder on the Amnesia game folder (\Program Files (x86)\Steam\SteamApps\common\Machine for Pigs) and Play the game! :)

Download: mediafire com/?9by0ddpvv62uzd1
Topic Source: http://forums.anandtech.com/showpost.php?s=02217d7f190e2ae3290be545f0ffa3e4&p=32767352&postcount=35
_______________

PICTURES:

*NOTE: This is Just An Example. Click on image to enlarge, please!!

Before: (Look at the beginning of the step, there are some jaggies)


After: (And After Apply FXAA Injector almost all jaggies disappeared)