Not really sequels except from my perspective of playing them. I played Ultima III on the C-64 first - incredible game. Have the cloth map framed. Later I went to play I and II to explore where the lore came from. While the lore itself was interesting, they were far more simplistic and boring compared to what they led to. I guess that's not fair, a sequel should try to raise the bar, and III did by a huge amount. But since I played them out of order, they felt like sequels to me that fell flat of what I had started off with.