There are so many random discounts everywhere for Lotte World honestly - Trazy, Klook, at the ticket window depending on the day and card and the month. Also, I have heard that the Magic Pass you have to buy on the spot, I'm not sure - but if there is something sold by Trazy or Klook, I would do that to save time. And I also heard that you have to apply for each ride for Magic Pass, not sure as I haven't used it for years, but I believe the general consensus is that so many people try to use it anyway that the spots are gone instantly and it's hard to use.

Whatever you do, don't go on a weekend. Go on a MONDAY morning right at opening time if you can. Weekends are insane and you'll wait 2 hours for even the simplest of rides.