How To Unlock The Letterbox Mode
After completing the story mode for the first time — on any difficulty level — you’ll unlock Letterbox Mode in the game options.
The screen goes to Options – HUD Display Settings – General – Letterbox – SHOW in the title.
Now start a NEW GAME for “That Cinematic Feel.”
It’s described as follows: “Toggle cinematic letterboxing on, just like in the good old days. This change is aesthetic and will not change the game’s output resolution or aspect ratio.”
Here’s a video showing the Classic Letterbox Mode: