Gyakuten Saiban is an adventure game where the player takes on the role of Ryuuichi Naruhodou, a rookie lawyer fresh out of law school. The game features five cases where the player must help Ryuuichi, as the defense attorney, clear the name of falsely accused defendants and prove the guilt of the real culprit. During the trials, the player must carefully listen to the witnesses' testimonies. He can then analyze the testimony, sentence by sentence, and "press" the witness for more information, or present to the court a piece of evidence that proves the witness's claim to be false. As lies and inaccuracies are exposed, the witness typically keeps changing their testimony until finally the truth comes to light. However, presenting wrong evidence or otherwise making errors will cause the judge to penalize you, and if you've accumulated too many penalties, he will lose his patience and declare a guilty verdict immediately.

Before and in between the trials, the player usually needs to take part in an adventure game-styled section where they conduct an investigation, travelling between various locations, interrogating people and searching rooms in hopes of finding evidence or learning some clues for the upcoming court session. There are four cases in total.