Some were not satisfied with the standard challenges.
Although the creators of Hollow Knight Silksong have prepared many difficult challenges, this turned out to be not enough for some hardcore fans.
A modder with the nickname TheWackyKnight introduced "Hollow Knight Death Swap - Silksong". The idea of the project is simple: depending on the selected setting, when dying or taking damage in one game, the user instantly switches to another.
The player HandowShandowed went a little further and fought two bosses simultaneously in Silksong and Hollow Knight (without switching between games — one controller sent signals to both).