As I recall, the games are in sections. When you search a room, you have to find all the objects in that room in a certain amount of time. If you don't, you have to replay the room but not the whole game. It's been a while, but I think that's right.
That said, some of the objects were really hard to locate.
"Best not to think about it. I don't want to fall to bits 'cos of excess existential thought."