Forgotten Riddles: The Moonlight Sonatas is a hidden object game where the usual list of objects to be found on the screen is replaced by riddles.
Besides the standard object hunt, there are three other puzzle types. In the "dollhouse" puzzle the objective is to click on certain places on the screen, moving mechanisms and interacting with objects and the environment to reveal secrets. In the secret rooms, the goal is to place objects in their right places. The optional music journal puzzle is a tile-matching game with musical notes that gives extra hints.
The game has two difficulty modes: Archaeologist and Apprentice. The first is the hard mode, with time limit and a reduced number of hints available. The easy mode has none of these restrictions. Each mode has a different ending.