Since Kakegurui Twin comes from the same mind as the original Kakegurui, and the anime is also produced by the same studio, there are tons of similarities between the prequel and the original series. From the strange gambling games to the predominantly jazzy theme songs, the fans of the original Kakegurui can quickly notice the resemblance between the two series.
That being said, just the simple fact that the prequel featured a different main character immediately changed the whole dynamic of the story. Because you see, Yumeko Jabami from the original Kakegurui is extremely confident, smart, and highly addicted to gambling. Some might even say that she can only feel truly alive when she is in the middle of a high-stakes gamble.
Mary Saotome, on the other hand, is not like that. Sure, she may be as smart and as shrewd as Yumeko, but when she first came into the Hyakkaou Private Academy, she didn’t enjoy gambling at all. After all, money is not something that comes easy to her family. The only reason why she can get into this elite school is that she is smart enough to get a full scholarship.
That is why when she suddenly finds herself having to gamble an absurd amount of money that she doesn’t have, she is shocked and stressed out. However, Mary is determined to be the best in this school, so even if she has to gamble her way to the top and is filled with anxiety and frustration all the time, she will do it. These distinct personalities between Yumeko and Mary are the reason why Kakegurui Twin has its own unique flavor that is different from the original.