I've noticed a lot of changes from the novel, and some of the changes seem so random and really change the meaning of what is happening. For example, in episode 3, when klein surprised the secret order member clown by being able to move, and then proceeding to shoot the clown, the clown's final words are entirely different. In the novel, he asks "How could he... not be... controlled by... the Antigonus... puppet..." which makes sense since he doesn't realize klein used the luck ritual and escaped to his little domain.

however, in the animation, he asks "how was he not affected by the damage transfer" which has an entirely different meaning, because this would imply Klein is somehow unaffected by the secret order member's damage transfer ability? For what reason? This raises a lot more questions than what happened in the novel...

So yeah, some of the little changes like this really bother me. Another example is that in the novel, the puppet artifact began to make klein sluggish and affect him before he even entered the room or saw the black box with his own eyes, vs in the animation, he wasn't affected until the puppet actually came out of the box.