Well, for one, the way the story is presented can vary. In manga, you have more control over the reading speed and can focus on details. Anime, on the other hand, sets the pace for you and might emphasize action scenes differently. Also, the art style might be slightly tweaked in the anime to make it more suitable for animation.
Well, that's a tough one. 'Gamera' has a pretty decent anime adaptation. It manages to capture the monster's power and the story's excitement. But opinions vary as different people look for different things in an adaptation.
The Kaiju No. 8 anime ending in the manga is a bit tricky to pin down. It could align with a significant event or cliffhanger in the manga, but there's no fixed rule. Usually, it's a balance between giving a satisfying conclusion and leaving room for more if the series gets renewed.
The anime ending of Kaiju No. 8 might not align exactly with the manga. It could be that the anime stopped earlier or covered a slightly different part of the story.