The big concept that distinguishes Palworld from Pokémon is its status as a survival crafting game, but as one player has now proven, it's not actually 100% necessary to embrace the crafting component. Plenty of essential components of Palworld are only achieved through building, from the Palbox used to revive Pals to most of the game's defensive options. Although avoiding the building process essentially reworks Palworld's difficulty could look impossible at a glance, seemingly impossible things sometimes just turn out to be brutally difficult.
The no-building run of Palworld was accomplished by Reddit user ballom29, who documented the feat in a video showcasing the fight with Saya & Selyne. As the final confrontation Palworld's Sakurajima update, Saya & Selyne as the ultimate test of a Palworld player's mettle, and beating them without any building throughout the game is almost unbelievable.
Without building, ballom29 had to use a lot of underpowered gear, and despite having a level 55 Necromus Pal in the video, the armor and weapons are surprisingly basic for the fight. A comment from ballom29 notes that Selyne was capable of one-shotting them, making the fight an incredibly high-risk scenario that happened to work out well on the 10th...