Brutal Doom 2 - Hell on Earth - Ultra Violence - Wolfenstein (level 31) - 100% completion

100% kills
100% items
100% secrets

This secret level is accessed from level 15 "Industrial Zone". There are two exits in this level. The main one proceeds on with the main storyline with level 16 "Suburbs" and the secret exit, taken here, goes on to the second secret level (level 32) "Grosse".