CUPHEAD STEAM WINDOWS 10
Since the brightness changed with the SDR content appearance slider, this game does not make use of native HDR, and is in fact merely tonemapped from SDR to HDR automatically by Windows 10 (so called fake HDR ).
![cuphead steam cuphead steam](https://steamcdn-a.akamaihd.net/steam/apps/268910/ss_380296effbf1073bbedfd480e50cf246eb542b66.1920x1080.jpg)
Windows version does not support native HDR, which was verified and confirmed by running the game on a HDR display while Windows HD Color was enabled (allows for HDR output to the display running in HDR mode) and confirming that the brightness of the game changed while manipulating the SDR content appearance slider in the Windows HD Color settings. Tested on the current Steam release of the game, and game will always prompt a Steam log-in unless Steam was uninstalled or creating a steam_appid.txt with its Steam App ID number.
![cuphead steam cuphead steam](https://i0.wp.com/sourcegaming.info/wp-content/uploads/2017/10/Cuphead-Review-H.jpg)
Locate the file for your save slot and open it with a text editor.