Most difficult levels in existence?

[BigOto2]

The thing is, the developers never programmed or tested invalid tiles into the game, and never used them, so that's why some of them crash the game while others just have some of the strangest effects (which make sense if you think about it). It just so happens that because the way the game was programmed, most of them have weird gameplay effects that can be used as new never-before-seen puzzle elements.