Here are some useful command line options Alan Wake (alanwake.exe) I found on the internet.

I don't know if they also work with Alan Wake's American Nightmare, but I would guess so.

-w: Screen width, e.g. -w1280
-h: Screen height, e.g. -h720
-window: Force windowed
-novsync: Disables v-sync
-showfps: Shows a frame rate counter on screen
-forcesurround: Forces 5.1 speaker mode
-forcestereo: Forces stereo 2 channel speaker mode
-nosound: Disables sound
-cleancloud: Deletes your save games and settings for Alan Wake from Steam Cloud
-noblur: Disables the in-game vector blur
-locale=xx: Forces a selected locale, e. g. -locale=en for English
-developermenu: Adds new menu [Developer Menu] to start screen to get guns, flashlight and more