As always, before using ResEdit, make a copy of the program that you will be working on.
Using a resource editor, such as ResEdit, open a "Levels" file. The resources that contain the information about the levels and lemmings are LEVL and ODDL. Open either resource and you'll see a lst of LEVLs and ODDls. Open one of these, and several fields(boxes with numbers in them) appear, which include rate, number of lemmings, number of lemmings required to reach the goal, minutes, climbers, etc. To change the number of climbers, enter the desired number in the box (only two digits). It a good idea to only edit the first twelve fields, unless you know what the rest do. Save and see if it works by playing Lemmings.
