First off, Ragnarok Online: Prequel is developed by China studio, Dream², 1 of the best browser MMORPG developers in the country. The Ragnarok IP is also officially licensed from Gravity, so this is not just another knockoff which China is famous for.
As seen in the trailer, most of the original features are intact, while I do see a couple of new features (or they were added after I stopped playing the original). With the basic classes and 1 advancement thus far, Ragnarok Online: Prequel has just ended its first test last month.
The dungeon system here is somewhat similar to games such as Dungeon Fighter’s and Dragon Nest’s, with a couple of difficulty levels. The monster cards are still there as well, thought it follows RO 2’s system where they are equipped on to characters rather than gears.