I made this zip file so myself and others can start new games without going through the prologue tutorial. Unfortunately there are still annoying pop up tutorials during the first mission and a bit after into the game. I wish the devs added a way to disable them.
In the zip file you will find the 4 difficulty folders. Select the difficulty you want along with if you want it permissive or "no one can hear them scream" (NOCHTS) mode.The difficulties included are:

•  Medium Permissive
•  Medium NOCHTS
•  Hard Permissive
•  Hard NOCHTS
•  Nightmare Permissive
•  Nightmare NOCHTS
  

I will add story later... probably...Step 1. Copy the folder found inside. It should be labeled something like

Campaign0_AutoSave_Otago_NewTurn_1 or Campaign0_AutoSave_Otago

Step 2. Next you will need to go to your game save files which is located here: \AppData\Local\ASF\Saved\SaveGames
You can get to the AppData folder by typing in %APPDATA% into your windows explorer address bar.
It takes you to roaming first so click the AppData again and then click local>ASF>SavedGames

Step 3. Make a backup of your current save files so that you can access them should something go wrong. It's easier to tweak the save file folder if you don't have any saves in it.

Step 4. Paste the save game folder that you copied earlier.
Step 4.5 You will also need to disable Steam Cloud sync if you have it on. Right click Aliens: Dark Descent and select properties and then turn off Steam Cloud sync.

Done! The only your SaveGames folder should look like this

backup (if you created it)
Campaign0_AutoSave_Otago
steam_autocloud.vdf

If you have any trouble getting the saves to work refer to Step 4.5 or drop a comment.

Thanks!