The base game won't accept any resolution above ( 1280 x 1024 ) and to fix this, you will need to edit some texts:

• Right click Second Sight on steam > Manage > Browse local files
  
• Right click " secondsight.cfg " > Open with > Notepad

• Look for:
  scr_height=480
  scr_width=640

• Change it to:
  scr_height=1080
  scr_width=1920

• Anything above 1080p resolution will cause rendering glitches
  
• Trying to increase resolution with AMD VSR or Nvidia DSR won't work, as those resolutions won't appear in game.
  
• You can increase overall image quality by forcing SuperSampling AA down below in Step 3

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The engine has a forced fixed aspect ratio of (4:3), you will need to adjust settings on your GPU to preserve aspect ratio and render the game with black bars.

.
• AMD :
  Gaming Tab > Display > GPU Scaling ON > Scaling Mode = Preserve aspect ratio

.

• NVIDIA :
  Control Panel > Display > Adjust Desktop Size
  ( check ) Scaling Aspect ratio
  ( check ) Override the scaling mode set by games and programs

1080p vs 1080p + x4 SSAA
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Anything above 1080p resolution will cause rendering glitches and trying to increase resolution with AMD VSR or Nvidia DSR won't work, as those resolutions won't appear in game.

Instead, increase image quality by going into your GPU settings and force SuperSample Anti-Aliasing. This will render the game at higher resolutions and downsample them back to 1080p.

• AMD:
  Gaming Tab > Games > Second Sight game profile > Advanced >
  
  Anti-Aliasing = Override application settings
  Anti-Aliasing Level = 4x or 8x
  Anti-Aliasing Method = Supersampling

.
• NVIDIA:
  Control Panel > Manage 3D settings > Program Settings > Select "Second Sight" >
  
  Anti-Aliasing - Mode = Override any application settings
  Anti-Aliasing - Setting = 4x or 8x
  Anti-Aliasing - Transparency = 4x or 8x Supersample

• If the game starts with weird resolutions with black boxes in the middle, restart the game.
  
• if the game doesn't reach 60 fps, this weird engine glitch will be fixed by restarting your PC.

No mod
With mod
^
To further reduce stretching, you will need to download a simple drag & drop text file mod into the game folder to force a proper (16:9) aspect ratio. Search for " SecondSight.WidescreenFix "