Load Any Level:

Just start dk2.exe with the parameter -level (levelname)
EX: dk2.exe -level level10

You can view all levels in your "DK2DIR\DATA\EDITOR\MAPS\" directory.

The Campaign levels are named form Level1 -> Level20

Exeptions are:
In Level 6 you have "level6a" or "level6b"
In level 11 you have "level11a", "level11b" or "level11c"
In level 15 you have "level15a" or "level15b"

The Secret Levels are named from secret1 -> secret5