Amazing, a must have if you own a ps2
Gameplay is amazingly fun, it never gets repetitive. There is also a LOT of environment interaction, which I personally find really cool. The combat system is pretty innovative as well, having an arsenal of weapons at your disposal, but also adding a system of hand to hand options that come into play when targets are hit a certain way. For example, a headshot can stun an enemy, and afterwards you can kick a stunned opponent knocking them over.
Bosses are stellar, each different and fun. I won't spoil anything, but they make the game for me. Getting through each boss fight really feels like an accomplishment, as most bosses will talk and interact with you before your fight.
This game also packs tons of replayability, as equipment can carry over from cleared game files. Also, there are other unlocked game modes that offer a change of pace from the original. Add in unlockable powerful weapons that get unlocked from beating other difficulties and game modes and you can play this game over and over.
In my opinion, nothing for the ps2 has come close to this game in quality. If you own a playstation 2, go out and buy this game.