Complex sentence: There is one song featured as an insert song in episode sixteen that did not come from the visual novel titled "Last regrets-X'mas floor style -" by Eiko Shimamiya from I've Sound's first album "Regret".
Split into simpler sentences: There is one song featured as an insert song in episode sixteen that did not come from the visual novel. It was entitled "Last regrets-X'mas floor style -" from I've Sound's first album "Regret".