SFFaFN, Extreme Challenge + Ending + First gameplay on Endless Mode (01:01:509)
Fanmade by @ButteryStancakes
Game link: https://gamejolt.com/games/slendrinas...
Edit (11/09/2022):
It took me a week, I made about 200 attempts before I managed to win this challenge. So leave like if you want other challenges like or more difficult than this one