Chapter 4 was heavily objective based. Vaults, Weather towers, the floating island, etc. Also more healing. It was different in the fact that there was clear goals to have in all or most stages of the game so you can have a clear advantage whether it was best loot or know where zones were gonna be.
But besides that its just fortnite, you build, box up and shoot people in the head with a shotgun. OG just gives people that "less is more" vibe.