Taxing 13: Upsidedown World
Good: Level Design (very good indeed)
Bad: Annoying
I loved this one. The problem is you would get a visual idea for a level, then have to make a level around it. You can see this a lot in Lemmings, 666, Hunt the Nessy, Every Lemming for himself, The Art Gallery, etc.
(Course... these were all done by the same person..
)
Also, the reason the levels were duplicated is they were for the most part too hard. So simpler versions were introduced to ease you in. The ment that many had the same solution. Very few "new" levels were done for fun & tricky...