Since Lotte World is celebrating 20 years of operation it's safe to assume they learned a few things from Disney World. In a nutshell, Lotte World is simply a mountainous indoor Disneyworld.
Numerous amusement rides--including a high speed full sized roller coaster--merry go rounds. ubiquitous refreshment stands, costumed animal characters, Broadway type shows, and a daily parade.
The Lotte company owns the adjacent mall--that resembled a cross between Harrads International and Saks Fifth Avenue connected by a marble underground tunnel to the amazing amusement center.
Like Disney, one price gets you unlimited usage all day long. Unlike Disney, admission was around $20. By 6:00 pm the kids passed out (as did I.)