Evaluating level designs

Stout does an analyses of the original SNES game 'Legend of Zelda and explains to the reader what a a good level design should have to be successful

-Level flow
how the level 'fits' together e.g the layout of the rooms
In Zelda the dungeons are carefully planned into a 'critical path' which means that its the original path that the designer has laid out for the player to take The player doesn't have to explore the whole dungeon to complete the stage, just room that are mandatory. The optional rooms and the shortcuts in the game makes the game feel less linear.
'...From analysesing the flow that the level design has, it strike's an excellent balance between giving the player the feeling of exploration and keeping them from getting lost'

-Intensity Ramping
Do monsters get more difficult as you move on in the game, does the player get to learn how the enemy work?
In general, no encounters should appear twice. In the dungeons each room should have a different enemy or layout form the one before, this keeps the player constantly being introduced to new things.

-Variety
Is there enough  variety in the game so the player wont get board or feel like the game is repeating on itself ?
Stout says that there might be a bit too much variety in the game with the enemies, i disagree with this completely,  yes, there is a lot of different monsters, and each of them require a certain way to kill them, as a player I think that it  makes the game less boring.

-Training
does the game 'train' the player to get better at the game?
In the SNES Legend of Zelda  they used to have a 'black room' where it was meant to give the player hints and train them. In the Japanese version it gave specific hints to the player, yet when it was translated into american the hints became pretty useless to the player, and so over time the developers got rid of the room.