Is it fair to say that Soul Reaver is the most impressive PS1 game from a technical standpoint?
It has large, interconnected environments that can be traversed without any loading screens (the game uses similar tricks to hide load times as modern games), as well as a surprising amount of environmental interactivity. You can pick up weapons, vases, torches and other kinds of objects that can be found all over and throw them at enemies. If you throw spears, they stick to walls (and stay there until you pick them up again), you can kill enemies by throwing them into fire, into deep water or against spiked walls etc, and of course there‘s the famous dimension warping ability, which transforms the whole environment in real time. The animations are also pretty good, probably on par with the average PS2 game.
It’s probably one of the few PS1 games that wouldn‘t need to be completely overhauled to be considered a good game by modern standards, since the game‘s mechanics hold up pretty well. All it would really need is modern graphics, improved combat and a modernized control scheme (though the original still plays pretty well compared to most other games from that era).