by Kharnel
This isn't an official list, but the fine folks at the >G forums have a game tracker going on that can at least give you a general idea of the difficulty of each environment.https://docs.google.com/spreadsheet/ccc?key=0AqClP82b_XgZdGJ...
https://docs.google.com/spreadsheet/ccc?key=0AqClP82b_XgZdGJ...