The story is not that good because the story doesn't really go anyway and it doesn't have a real end goal. Some people may say that it makes the story unpredictable but the problem is Re:Zero is not anime original.
Also like to mention the many plot holes that Re:Zero has like how did Subaru get hes powers, when did this start, why are some of these characters in and all of the sudden they are gone and never seen again, are they any other consequences when Subaru dies, who is Emilia, What did Subaru do in hes past life back in earth, why does he have these super powers and the list goes on and on. It's doesn't really make any sense because Re:Zero like to throw in new characters that barely do anything in the story.
World Building of Re.Zero is okay at best because while the show explores Kingdom of Lugnica well the other races like the witches, monsters as well of the labing nations, timelines and the world history is never explained at all. But hey least its better than Akame Ga Kill world building which is non existent at all.
Last thing I want to mention it tries to be a deconstruction to the fantasy genre but it fails miserably because the story is a poorly written mess.
Do you know that Episodes 15 is one of the worst written episode I have ever seen because not only it relayed on edge factor but just the overall writing and direction was a complete fucking disaster.
Overall the story is bad at best and at worse is awful.