I love Sengoku's gameplay more. But lore-wise, Rance Quest could be better. You can understand much more of its world compared to Sengoku which only focus on story about JAPAN.
I still remember the feeling of playing it for the first time without any guide/walkthrough. Things went well for about 50 turns until the boss event which make me realize I played it all wrong (only focus on troops/field battle, not levelling up Rance in dungeon so I can't beat the hard boss). The bitter feeling of how my 30+ hours of hardship is all for nothing made me delete the game and had not played it for almost a year. Then I suddenly feel like giving it another chance, this time I did a bit of research and play it correctly. Then I was completely addict with the game, played it for 200+ hours to clear every routes. The gameplay is very fun and challenging, the lore is great. I didn't know lots of previous heroines at that time so I couldn't enjoy it to the fullest but just the story with Sill and other Japanese heroines are great enough. After clearing Sengoku Rance, I played Rance 01-6. It's such a great series. 01-02's story is not much, but after 03 it becomes much more interesting. I'd even say it's the best fiction ever created. Can't wait to play Rance X in English.
