Prince of Persia: Warrior Within
They improved the combat system in comparison to the previous game. It's much better and more fluid this time around. The game is also much larger and longer. The length of this game is precisely why I dislike it a bit. On one hand they pushed the limits of the PS2's hardware. One the other hand they made this game quite exhausting. Better HUD, more powers, more combat tricks. The plot bears some resemblance to "Back to the future 2" because you see yourself from a different perspective while running back in time in the last part of the game.
The level design is awesome. Great design, great traps and challenges. However, the idea that you have to backtrack and traverse the same places multiple times is what made this game too long. I don't know if this concept was a way around hardware limitations of the time. But it becomes tiring to traverse the same places again and again. The idea of representing the same place at different times, present and past, is cool but at the same time made me confused. More than once I traversed places during the wrong time period, forcing me to journey back and forth.
It's a matter of personal preference, but I liked the realistic art style of WW more than the cartoonish style of PoP.
For modern standards I find that the boss battles in WW are excessively long. Take Kaileena for example. She repeats the same pattern over and over. It's easy to get the pattern. The fight with the boss Dahaka is excessively hard. The only way to win is to abuse the time powers in a way that chips away his health as fast as you can. Else the battle is just impossible to win.