In another thread, it was clarified that "multiple targets" applies is limited to targets at a single location (when encounter is spread over multiple locations). So how is "multiple close targets" differ from just "multipe targets"?
It's a narrative difference, and is fully dependent on you and the game master equivalent deciding what it means.
It's an important distinction also, because it will mean that the GM is deciding whether certain character types are simply going to overpower certain scenes or not.
The good thing is is that you can be flexible with it also, so when you *want* the scene to showcase a large number of multiple attacks, while other times it will be more restricted.