It's pretty different to the anime, although I imagine later volumes will become more narrative-driven and focused on the protagonists. This first volume feels like a genre parody that sometimes happens to star Saitou, Raelza, Morlock and Rafanpan. It has other kinds of parody too. There's a hero party assembled by committee, featuring a pisstake of the Camelot legend. There's a faintly disturbing duo where one girl loves the other girl's wounds.
The cast, world and concepts are the same, though. The anime's pretty faithful. Saitou's a Japanese handyman who's been summoned to a fantasy RPG world and was delighted to find friends who value his skills. Raelza is the party's fighter, Rafanpan is a fairy with healing magic and Morlock is a senile disreputable old git (and wizard).
It's definitely an RPG game world, with the characters knowing their own levels on page 11. There are real-world references, e.g. Saitou considering and rejecting the dangerous idea of building guns. There's also a cleaning robot and mobile phone chat. Other content, though, could be called either edgier or sophomoric. The king's court has petrification, demon lords and severed heads, but there's also penis-sucking. Morlock owns a book-box containing a large severed penis, labelled "mushroom, this is a mushroom", which for some reason everyone likes sucking. Yes, Saitou's surprised too.
The mini-chapter can have their own little storylines, but there's hardly any overall story. The volume has lots of tiny chapters, most commonly four pages long although there are longer sequences of up to a dozen pages or so. The characters come across well, though. Raelza fancies Saitou and can't bring herself to say so. Rafanpan doesn't feature much, but we learn about her financial issues and her pride that stops her from accepting charity. Morlock's the funniest character because he's so terrible, forgetting his spells and regularly dragging down the tone. He visits casinos and tries to chat up a naked succubus.
The art's a little unusual. I don't think it's been inked (except for the volume's final chapter). It lacks that finished look that inkers give you. I think we're looking at the original pencils, either digitally drawn on a tablet or scanned and then line-intensified in something like Photoshop or GIMP. It's also, though, not very good. The artist has a problem with girls' faces, while Saitou can drift off-model. The only regular the artist's truly comfortable with is Morlock, with all that attitude and facial hair. (Elderly faces are the best.) That said, though, I prefer Rafanpan in this more delicate pencilled style. I was slightly reminded of 19th century fairy illustrations and people like Walter Crane and Arthur Rackham.
It's not a bad volume. It's different enough from the (excellent) anime to be worth reading in its own right. Natsuki read it, thought it was good and was interested in buying more volumes. I am, though, pretty sure later volumes will settle down and have more narrative.