Operation Mania is a time management game based on Hasbro's classic board game Operation. The game puts the player in the shoes of Dr. Humerus, and is all about curing patients to earn money that can be used to improve the hospital and in the end achieving fame and fortune.
As in other time management games, the game is entirely controlled with the mouse. Patients that arrives to the hospital starts out in the waiting room and their needs are expressed with icons above their heads. Depending on what the patient needs the player has to drag the patient to the right location in the hospital. Clicking on that patient will then send the doctor that location for treatment. When the treatment is completed, the patient leaves money behind that the player has to pick up. Each level is on time and each level ends when both the timer runs out and no patients are left.
There is two kinds of patients: regular patients and emergency patients. These can have one of the 22 maladies that exist in the game. Surgery for regular patients can be done automatically, while for emergency patients surgery is done by playing a mini game. Mini game surgeries can also be performed on regular patients and players will then earn a bonus if successful. Players can also multiply their earning with colour chaining and action chaining. Colour chains occurs when patients of the same colour are placed at the same location. Action chains occur when the same treatment is performed consecutively.
All of the maladies in the game are made up and are intentionally wacky. For example, the first malady the player comes across is butterflies in the stomach and is treated by catching the butterflies with a hand net, while avoiding the apples the patient has eaten.
The game's story mode consists of five different hospitals that each has seven levels. There's also a marathon mode that can be unlocked by playing the story mode.