The protagonist starts off very flawed, but by repeatedly experiencing the results of his mistakes he goes through truly profound character development. That's the main structure the story is built around.

A lot of people say it's an anime about "suffering" and that it's "edgy", but the suffering and edginess are just tools that the author masterfully employs to develop the protagonist's character. The pain and tragedy aren't there just for show, they're there to prove a point (A point which I don't think I can explain well in words, so I'll let you figure it out).

The plot is complex, but skillfully woven in a way that moves the story forward, introduces and develops characters when they're needed, without hindering the entertainment value of any of it. It's still somewhat unbelievable to me how Tappei managed this, while still making so much sense. I have yet to find a plot hole that wasn't resolved after some exposition.

Speaking of characters, they are the greatest strength of Tappei's writing. Every character, and I mean every single one feels like a real person. Their motivations, actions, words, expressions, all feel believable in relation to what the anime teaches you about them. I've never thought "Is this really what [character] would do in this scenario?", either while watching the anime or reading the light novels.

Still, there are many supposed issues you may stumble upon when watching this. One of the main criticisms is that Subaru's power, Return By Death, nullifies all stakes the story could have. Certainly, in solely physical terms, Return By Death makes Subaru invincible. "If only he'd kill himself more often, he could get anything he wanted!" Yes, you're right. This option has already been disclosed by the author himself, in the form of the Kasaneru IF side story. But the problem is a simple one: Subaru doesn't want to die.

When Subaru realized he had an indefinite amount of lives, he automatically defined the value of one of those lives as zero. Makes sense, right? But the fact that this logic doesn't apply to his own life was something Subaru only learned a lot later.

Subaru feels guilt because of the mistakes he's made, even if the results of those mistakes no longer exist. Subaru doubts his capabilities because he's seen himself fail so many times before. That's why this story isn't about Return By Death. The objective isn't to learn to use it as effectively as possible, it's to evolve and eventually stop relying upon it.

If you find some part of the story illogical, chances are that it will be acknowledged and explained, even if implicitly, later on. That is why a considerable amount of people disliked the anime's first season, but grew to love both the first and second seasons when the latter aired.

Overall, this is an anime I'd recommend to anyone looking for something to watch with full focus, not just something to have on your second monitor while you play something else. Re:Zero is dense, and hard to digest. Even though it's my favorite series and I've watched the anime 4 times, it's still hard for me to marathon. Still, I'd recommend rewatching it at least once if you enjoy it enough. You'll catch a lot of details that just slipped past you the first time.