The puzzles at Bergen Mine ruin it for me.

*EDIT*

After beating the dungeon I now know the truth. The developers feed on the rage of the players. Without our agony the developers cannot suceed

[lachsen]

The fun of a game is often connected to a challenge and this might border to frustration when it's too difficult.
Reducing the frustration for some players might make the puzzles too easy for others. You can't make it perfect for everybody...