Despite the first chapter being rather boring, it sets up the story well. The manga is about a dude who goes to another world in his dreams and can take certain things over to that side, such as his bento. So he packs lunch every day and goes to the other world to level up and grind experience and such.
One day, he dies in a dragon's nest. However, he did not die alone but instead with his elf friend Mary. When he wakes up due to dying in the dream world, he finds Mary next to him.
The story basically revolves around Mary
getting used to life in Japan and their adventures going back to the dream world. It uses lighthearted banter to develop the world and philosophy behind these alternate realities and has cute interactions between the characters.
I like how the author pays a lot of attention to minor details, such as how food might not be as advanced in the other world because cooking has not been developed enough technologically due to everyone becoming an adventurer and fighting over stuff.
It's good. Kazuhito is shown to be a little lazy with his trademark "sleepy eyes" and that distinguishes him somewhat from the average isekai protagonist. He's also a young salaryman, not an age group you see too often in this medium. He looks happy most of the time because he is happy most of the time, and that's consistent enough for me.
Mary's reactions to things are cute, she's drawn well and not oversexualized like many elves are in fantasy manga. Her expressions are one of the highlights of this manga.
Kazuhito isn't an overpowered mc in the slightest, and this is one of the main reasons the story appeals to me. He does seem a little broken in some parts but this is explained by his unusually long lifespan. His friendship with Mary seems to be genuine, despite all the jokes about it revolving around food, and he's an overall normal guy who acts normally. This is about as relatable an isekai protagonist is going to get.
Mary seems haughty at first, but she is revealed to be a good person - er, elf. This isn't to say that she's a cardboard cut-out tsundere, it's just that she seems to have this air of superiority (she does know more about the other world than Kazuhito, and she helps him in this aspect) that she immediately drops once she tastes Japanese food. She's also a proud magician and it's noted that she doesn't want to ride a car until she understands how it works, which is pretty impressive and fits well with her personality. Her reactions are pretty wholesome.
The dragon is relatively new to the manga but she seems like a rather fun character as well, although a bit cliche. The worldbuilding is also consistent regarding all of the side characters.
I didn't particularly see any specific aspect of this manga that excels. Of course, this isn't to discredit Nihon e Youkoso Elf-san in any way, because it is a good manga on its own. But it's not anything groundbreaking, even though it is a well-rounded manga that I encourage you to check out if you're interested.