The games here are

Final Fantasy VII (1997) vs Final Fantasy VIII (1999)

Parasite Eve (1998) vs Parasite Eve 2 (1999)

Resident Evil 2 (1998) vs Resident Evil 3 (1999)

(You could place Parasite Eve between FFVII and FFVIII since it came out between the two and was used to prototype some of the tech for FFVIII)

The leap in quality with the human character models is especially impressive. Look at Sephiroth's beautiful visage here and just think that Square went from that to feeling like their animation was convincing enough to carry an entire sci-fi drama movie with a realistic human cast in less than 5 years