[[WMG:The explorer is already cursed to death]]
It happened when he/she picked up the idol. I know it's kind of obvious, but it's not outright stated in game either.

[[WMG:The explorer is already dead]]
He/She is in hell, and is cursed to eternally run an endless path in a non-Euclidean environment with no exit.

[[WMG: The game takes place in the Skullmonkeys universe]]
As you're chased by Skullmonkeys