Hi,
there is one thing, that bothers me most about the maps I upload. It seems that I can not choose the difficulty of my maps correctly. If I think the map is hard, they beat it in record time and comment, that it is easy. On the other hand, there was one map that I thought is easy, especialy for these guys that rush over the harder maps, and I am the only one that scored there...
So my main question: What are the criteria for the difficulties?
It is recognized by all that the difficulty rating is flawed (has problems). Virgil has indicated that he might remove it from future map classification systems. Right now what is used more is the time to complete a map - there are filters for that as well. But even so, some maps that can be completed in a very short time may be near impossible for the average player (http://knucklecracker.com/creeperworld/mapcomments.php?id=773&page=), while other maps that take an eternity to play are merely repetitive steps of blasting your way through a maze - once you know how, it merely requires you to do the same thing 50 times over - which is not hard.
Some cynical players even rate their maps a certain difficulty in the expectation that it will attract more downloads.
So focus on making a map that you will enjoy playing. Then if others like it, regardless of hard/easy, you have achieved your goal.