Start the game with the "-developerkeys" command line parameter. To do this go under the properties of your Max Payne desktop icon (right click on the Max Payne icon, then select "Properties"), then change the entry for the program to "Target: "C:\Program Files\Max Payne\maxpayne.exe" -developerkeys" or something similar. While playing a game, press [F11] to display the statistics screen, then Press [Page Up] or [Page Down] to cycle through the character models.