The Evil Within is not just about clearing the 14 chapters one way or the other. Even after you are done with the whole campaign, there is a lot more than you can do.
In fact, there are elements in the game that only get unlocked after you have completed the campaign once. Among these are the special unlockable weapons and some unlockable game modes.
The Evil Within Weapons Unlock
In a special mode that gets unlocked after you are done with the campaign once, the New Game+ Mode, you will be allowed to use some of the special unlockable weapons.
Each one of them comes with a special edge over the rest of the weapons you had previously, but in order to get your hands on them; you will have to work hard.
The machine gun will be unlocked only after you have completed the full campaign.
Just like the machine gun, the Rocket Launcher will also be unlocked after you are done with the campaign. It is similar to the one seen in the last chapter, and you can use it to kill certain bosses who are otherwise too hard to beat (like Laura).
You can get the Automatic Handgun once you are done with the archive.
This baby gets unlocked only after you have worked hard. You will have to find all the 28 Map Fragments in order to get your hands on it. It is actually a pistol that can fire bursts.
High Powered Sniper Rifle
Just like the burst handgun, you will have to find all the Map Fragments in order to unlock the High-Powered Sniper Rifle. It is much more balanced and much more powered weapon than the standard Sniper Rifle.
Nothing compares to a devastating melee attack but you first have to earn it. Only after you have completed the campaign on Nightmare difficulty will you unlock Brass Knuckles. They will make your melee attack much more powerful.
The Evil Within Game Modes
There are at least three special game modes that get unlocked after you have proven your worth in the game. Mostly, you will be allowed to play them only if you have completed the campaign once. They provide you the game with tweaks to the difficulty and sometime the content.
Once you have completed the campaign this new game mode will be unlocked. It lets you replay all the saved chapters again but this time with special unlockable weapons.
You only get to act like a pro when you have proven your worth! This mode kicks in after you have completed the whole campaign. It gives you the game at a much harder difficulty with less ammo and much more powerful enemies.
This is not for the faint-hearted. Once you have completed the campaign for the first time you get to play the AKUMU Mode where Sebastian will die only after the first hit.
If there is anything confusing you, let us know in the comments below and we will be more than happy to help!