I honestly don't like very long level. It can be a bit difficult, but it doesn't mean I need to walk around 3 minutes straight to the end of the level (excluding the time to think).
I usually like people who play my levels to know if it is gonna be a easy or difficult level. That is the reason why i created 3 albums "Easy", "Hard" & "Trick". I post my levels based on the kind of level they are. But yeah than again there is a misconception where a level that i find easy others may find it hard or vice-versa. So there is not really much we can do about it other than people downloading levels and finding it out themselves whether the level suits their taste. I personally like to add few trick here and there in my level and without the knowledge of how the trick works it would be unlikable or even frustrating for players to play it. So probably giving a Demo in my "Trick" album to get introduced to a few tricks, they will be able to complete the levels in the "Hard" category. Apart from that I don't think there would be any direct solution to specify a certain level easy, medium or hard.
Well depends if you have more easy levels than hard, example if you download mine (don't) then you've came for expert level if you've gone for a random user that uses random levels it's more scattered around
I agree with many opinions said here about difficulty. I think that too hard levels are not always better than easy ones. I always prefer levels that are based in a single idea, so we have to find that and then solve the level. I think too that exploit based levels must be relatively simple, but the finality of a game is to be fun. I especially like levels that are a kind of "escape room" resolvable with logic, with a bit of surprise and/or joke in the gameplay. However, I understand that some people loves complexity per se. Then Mekorama's forum is the best place to find the hardest levels created ever.
Fortunately, we have been screening levels for a very long time specifically to avoid any uploads that would not have a solution. If anyone finds a level that they suspect may not have a solution, then they are kindly asked to "Report" the upload to alert the staff.
Normally I prefer logic levels with medium difficulty. With something original and a well defined objective or path.