The Agency of Anomalies: Mystic Hospital
A rather challenging casual point-and-click adventure with many good hidden-object scenes.
The story doesn't make much sense, but is told well, with appropriate graphics, sound, music, and occasional voice acting. All in all I strongly recommend it to fans of the genre.
Note that though the game features achievements, they are not linked to Steam.
This game is the first in a series of four games: Mystic Hospital, Cinderstone Orphenage, The Last Performance, and Mind Invasion. The fourth game is not currently onz Steam.