Yes, there are some deviations from the original. Some of this is streamlining - cutting out things that just weren't all that necessary or are mostly textual. Some of it is adaptation - certain things show better visually if the details are altered, or are extremely hard to depict precisely as described, etc. Some of it is for the audience - Webtoon audiences have a slightly different flavor of thing that they prefer, and a few tweaks have been made to give it more of a balance between action and thought than the original had.
If you come across this story on Amazon, it's taken without permission from the author. Report it.
I'm not too fussed about the changes, I always knew stuff like that would happen and there's nothing too egregious. I'm an active participant in the creation process and doing my best to tweak things here and there to make them run smoother. I know some people wish certain details were kept in or the like, but I think a lot of people will enjoy it, and I hope you do too!
There is a separate discord here for discussing the webtoon.