Dominique Pamplemousse in "It's All Over Once The Fat Lady Sings!" is a claymation point-and-click adventure game that is played as a full musical, complete with singing and entirely in black-and-white. The title character, Dominique Pamplemousse, is a gender ambiguous detective who has fallen upon hard times and is unable to pay the rent. Dominique soon takes a case from a record executive who is searching for her missing client, but soon learns there is more to the case than was first thought.
Most of the puzzles are revealed through conversations, as new information opens up additional investigation options. There is an inventory to store items, but clicking the fitting object in the game environment will automatically select the correct item from the inventory.