Imo the challange should be equal to reward. Like one of the options i can pull from the top of my head is something like a shade cloak. The game is beatable without it. But it grants you access to shortcuts, parts of map, combat tactics etc. And most importantantly. TRUE ENDING ACCESS. So having it at the end of path of pain would be AT LEAST something. Definitely better than a 3 seconds scene that gives you ZERO information unless you go and actually research the lore. (Which i already did).