Complete the indicated requirement during the game to unlock the corresponding ending.

Unlock Alternate Ending #1:
Tell Minette Heather sent her one of the threatening letters and Heather will not be nice to you at the end.

Unlock Alternate Ending #2:
If you don't tell Minette about the threatening letters you will be on the runway in Heather's fasion show at the end.

Flush the toilet ten times in the dark room at Dieter's studio. You will hear the sound of a chicken. Look in your inventory to find a blue egg. Go to the development table and all your negatives will now be developed.