The anime doesn't have a problem randomly mixing in jokes, which a lot of times just got me off guard and I burst out laughing. The anime doesn't take itself too seriously, which is good! It also has a lot of easter eggs, although some of them require you to have a considerable amount of knowledge regarding anime or games. Everything related to the story is explained in great detail - to my surprise, I couldn't find any contradictions anywhere. Everything makes sense! It's not about whether the heroes will win (gee, of course they will), it's about how they will win.
So there's a girl with superb intelligence. She could speak and solve puzzle games when she was 1 year old. Anything that has a system, she can figure it out and use it to her advantage. She can calculate the probability of your possible moves in a game of chess several hundreds of steps ahead.
Her brother might not be that smart, but his specialty is "reading" people. He's a manipulative bastard. He knows so well what you are thinking it's actually intimidating. He will tell you what you want to hear ad get you to do what he wants you to.
Together they create [blank]. The gaming group without a name. No one has ever beaten them, be it videogames, which take skill, or gambling like poker. They are a perfect combination. One day they are reborn in a fantasy world, where everything is decided by games, rather than war and killing.
One minor complaint might be that sometimes the explanations of their strategies and the rules is sometimes too fast and you can't absorb all of that right away.
