[maximus_asinus]

An example of Haro's advice would be the top corner cliffing, a player could jump down to the second level but not the third forcing them to retrace their steps for however long.

Another example is the areas that are only wide enough for a single player to pass through. Another player could easily come along and pin a player in one of these areas. That would be incredibly frustrating for a newbie don't you think?