Feels like an official prequel. I LOVED revisiting the Underground. It shows a couple of familiar locations from a new angle and I ADORE the newly added western themed areas.
200 hours of playtime and multiple playtroughs later I still want more! - half a star because I don't like the repetitive optional dungeons plastered all over the game map and getting the stones for weapon upgrades is kinda tedious for repeat playthroughs.