In Dead Island, are there any collectables which I can only get in one particular situation and then never again?
Like, are there any areas with collectables which I only enter once in the story and then can't go there again?
I've heard that sometimes alicia's house is only available during the quest uninvited guests and there is a skull drop off and skull pick up there. Also when you arrive at the prison there are quite a few and they have to be found before the game is complete. But if you ever find yourself missing one you can always join someone else's game because it saves the certain ids and collectables you already have and don't.
When you reach the end of the main quest chain and reload your save it will ask you to if you want to reset quest progress (not your char levels and stuff, just quests) and you start again right at the beginning but with you levelled char.
So it seems you can repeat the whole game on the same char at least twice and therefore can pick up stuff you missed (in theory at least).
Look for weapon names in a orange outline.Those are the kinds you can get but will never see again.