As someone who reads the LN, I can definitely say that this is a really good adaptation. They changed some scenes/pacing a bit, but it was understandable so they can compress the LN to a Manga format. This manga also helped me to imagine what some characters look like in the LN (Especially at Volume 1. There was no illustration of Nell, the Ogre with too many Ds on his name, or Randal so reading this manga is really helpful!)
Overall, give this manga and Light Novel a try! This series is actually the first LN that I've read. It's light-hearted and simple at first, but the story will slowly build-up and become more exciting!