Originally Manhunt 2 was going to have a 'good and bad'
ending, however, after having to alter the game in order to
get an appropriate age rating Rockstar decided to stick with
one singular ending and instead make the other a bonus upon
completion of the game.
After completing Manhunt 2 for the first time on either difficulty
selection go into the episodes menu, select relive episode
and go onto page two, if you go to the bottom of the page
you will see the option to play "Release Therapy".
This is in effect the alternative ending. You play this episode
as Leo Kasper as apposed to Daniel Lamb.