CS is hands down my favorite VN. But, I have to agree. If there is one thing I'd criticize about CS, it's the sex animations particularly in CH5 and CH6. They're good animations, but the animated models themselves look very different from the characters in the static renders, Particularly Mallory in CH5. She looks like someone else entirely in the "Two O'Cock" scene.
Also for some reason, Mallory's skin tone sometimes looks grey in that scene and a couple others. Almost like she's desaturated when standing next to Alex. It's a bit odd. She's still adorable though.