> If you take 2 minutes to read the user guide of both softwares, the difference is obvious.

> Reshade requires you to select the game executable and inject tools into the executable

> Chroma does not require you to point to the game

Did we read the same user guide? As per Chroma's:

> Right-click on the Chroma window to get the menu list of all applications which are running on the PC.

> Select the application which you want to capture from the menu list

You're right the implementation is different. Reshade injects itself into a games rendering pipeline, while Chroma seems to read the screen (or a window, I can't really tell from the code) and create a window which shows a region of the screen with the shader applied.

In both scenarios a QA person could work with a generated build of the game and apply colorblind shaders on top of it, without having to ask a dev to add 'colorblind testing mode'.