Use the following level names with the map command.

Map Name - Level
demo1 - Original Hexen 2, with new features
keep1 - Eidolon´s Lair
keep2 - The Village of Turnabel
keep3 - The Duke´s Keep
keep4 - The Catacombs
keep5 - The Hall of the Dead
tibet1 - Tulku
tibet2 - The Ice Caverns
tibet3 - The False Temple
tibet4 - Courtyards of Tsok
tibet5 - Temple of Kalachakra
tibet6 - Temple of Bardo
tibet7 - Temple of Phurbu
tibet8 - Palace of Emperor Egg Chen
tibet9 - Palace of Inner Chambers
tibet10 - The Inner Sanctum of Prævus
thomas - Intro (EGO version)
monsters - Silly level with monsters and no exit