ZERO ESCAPE
gameplay
puzzle
The puzzle part is when the player must solve the puzzles that are blocking their way in order to progress through the game. There are 16 escape rooms in total. The game also contains a calculator with a digital root function to aid in escape rooms.
visual novel
The visual novel part in which the player can talk to the other characters and make decisions that affect the story of the game. Junpei or the other characters may die depending on what doors and dialogue choices the player makes.
extras
Unfortunately, the player must re-watch cutscenes and re-solve the puzzle rooms to obtain all the endings in the DS version. This was fixed in the iOS, Vita, PS4 and PC versions which added a FLOW Chart.
Although in-game the ship will sink in 9 hours, there isn't a single time limit in the entire game so the player can play the game and solve all of its puzzles at their own pace.