Success rates vary per room but are about 17-26%. All escape room games are challenging and those who succeed often do so with only minutes left on the clock.
Players typically do not play the same game another time. If they wish to do so, they can ask the game master not to explain the rest of the clues.
If you want to play a room again, you will need to book the entire room so you are not spoiling the game for new players by quickly solving the initial clues.