I enjoyed the Zarnag battle way more in the manga adaptation, it felt like a high-stakes battle with some real close calls, so much that and end of it instead of celebrating they just huddle together to calm down. Definitely one of my favorite moments of the manga.
That being said, at this point in the story Yuke is way more likeable in the anime adaptation. Early on in the manga he's very lacking in confidence so they keep using the "Yuke does something amazing, thinks it was nothing special, everyone goes crazy about it" setup way too often.
Another welcome change is the post-battle handling... in the manga there was a dumb plotline about Yuke risking punishment for using an unregistered spell that they skipped here. But I do wish they kept the explanation on what exactly Prismatic Missile does, since it was a very fitting "trumph card" for Yuke - it's a massive pile of negative status effects.