A Sucky Game is the result of making a poor idea chip selections in the Disc Developer. This will lead to creating a disc with an additional negative effect.
See also: Godly Game.
When creating a Sucky Game you will receive all of the normal effects from the idea chips used to create and also receive a negative bonus effect. These effects can range from lowering defensive capabilities and decreasing gained EXP to even decreasing your HP and SP every turn.