The anime adaptation may add more visual impact. In the web novel, you have to use your imagination for the magic and battles, but the anime can show them vividly. For instance, Rimuru's evolution scenes are more spectacular in the anime.
The unique concept of being reincarnated as a slime is really interesting. It allows for a fresh take on the isekai genre. Also, the way the slime, Rimuru, builds his own community and kingdom is engaging.
In the web novel, the story progresses in a more text - heavy way. There are long descriptions of Rimuru's thoughts and decision - making processes. In the anime, it's more streamlined. For example, when Rimuru builds his own kingdom, the web novel goes into great detail about the negotiations with different tribes, while the anime shows the key moments.
The 'How I Was Reincarnated as a Slime' manga is the original source, giving more depth. The anime makes it more accessible with animations and voice acting. Both have their merits, and it often comes down to personal taste in how one enjoys the story.
It's quite close. The anime adaptation of How I Got Reincarnated as a Slime mostly sticks to the manga, with just a few minor differences that don't have a big impact on the story.
Rimuru starts as a rather weak slime, but as the story progresses, he evolves through various means. He absorbs knowledge from the beings he assimilates, which broadens his understanding of the world. His experiences with forming alliances, resolving conflicts, and building his own territory contribute to his growth. He becomes more confident, more strategic, and more empathetic towards others, which are all signs of his remarkable growth throughout the novel.