It’s hard to describe this so really, if you have the time you’re maybe best off watching some of the footage. But at its heart this is a sort of online spooky ghost story thing where someone has created a completely fake 1997 Sony PS game and built up a narrative: They claim they found it in a second hand store with an obscure message and have uploaded a YouTube of them playing it to convince someone that it’s real.
Towards the end they hit a cheat code and sort of enter an underthing type of situation.
Those are the first two but there are about 13 under the account or something. Apparently there are references to
which is fairly grim as reading goes.