Why Everyone Hates It: Prince of Persia: The Sands of Time is, by popular opinion, one of the best games ever made, with wonderful attention to detail, wonderful Ico style exploration puzzles, a great sense of humor, and a great visual style. Then they went and followed it up with Warrior Within, which completely ruined all that and turned it into some sort of blood-splattered, heavy-metal themed spree of violence with an incoherently screaming ball of generic angst and rage fighting various girls in offensively slutty outfits.
Legitimate Issues With the Game: Honestly, I agree 100% with more or less every single negative comment I have ever heard regarding Warrior Within. The only potential exception is when people mistakenly claim it shifts the effort off puzzle solving, instead placing it on mindless boring combat. That's only really true for the first few minutes of the game.
Why I Like It Anyway: If (and admittedly, it's a big if) you can bring yourself to overlook all of the... added testosterone shall we say, Warrior Within shows an amazing degree of improvement over its predecessor in terms of puzzle design, pacing, and ambitious design. It also has one of those stories that ties everything up quite nicely when you look back on it.
Before we get too far into things here, let's take a look at why the overall aesthetic of the game wound up so jarringly inappropriate for the series, shall we? Ultimately, it all comes down to a matter of confidence. Nobody evidently knew at the time what a wonderful game The Sands of Time was when it was released. First, the developers made no attempt to set up a plot hook for a sequel, as they have with all their games since, forcing Warrior Within to shoehorn itself in a bit awkwardly. The in-game rationalization for the game's faster pace is that there exists an unstoppable monster who exists solely to hunt down and kill anyone who creates a paradox using the sands of time. An interval is skipped over between the two games, during which the prince has been literally constantly running from this creature, and looking for some way to stop it. If this was at least hinted at in the earlier game, it would have been a much much easier premise to swallow.
More importantly though, the perception a Ubisoft was that The Sands of Time didn't appeal to most of the audience they hoped it would have. A bright, somewhat cartoony game continuing a series whose fan base had long since moved on evidently didn't make a big enough splash in 2003. Someone figured that giving the sequel a darker tone and placing more emphasis on combat would widen the game's appeal. In moderation, this would have probably worked just fine, but as anyone who plays it can see, they went more than a little overboard. In other words, blame marketing for this one.
Let's take a look though at the one thing this grab for a wider audience actually got right. Combat. Battles in The Sands of Time were, I think most of as can agree, the worst part of the game. Periodically, we're forced to take a break from flipping off flagpoles and running along the side of walls to fight a room full of sand people. As if that weren't bad enough, combat really just boils down to working out the one maneuver that consistently leaves everything ready for a finishing blow with your dagger. It get's quite repetitive quite fast.
Warrior Within on the other hand, makes combat a much more fun and organic part of the game. Trading in the dagger for one of the more practical artifacts of time, you can now fight with a permanently available sword in one hand, with the other hand free to grab any of the various weapons held by your enemies. This adds a fair deal more variety to your options. More importantly, rather than throwing enemies in as breaks from the puzzle solving, they're constantly peppered through the entire game, usually in much smaller numbers, frequently adding to the challenge of puzzle solving. While The Sands of Time might have you navigate a trap filled corridor, then fight a group of sand people, Warrior Within will throw a few sand people into that very corridor, found halfway along balance beams or even set to run out and meet you as you run along the side of the wall before leaping to a small handhold on the other side.
On that note, despite being designed to draw in a wider audience, Warrior Within follows the design philosophy of starting the difficulty of its puzzles at the highest level the previous game reaches. Simply put, large portions of the game have a distinct lack of solid ground. More specifically, the game features the prince constantly flipping back and forth between the present, where the game's setting has fallen into such a state of disrepair that travel involves constantly leaping and climbing through stray bits of wreckage, and the distant past, where things are generally more intact, but so are the many many many traps lining the hallways. Then of course we have those moments when the paradox-hating monster that's largely driving the plot will come crashing through a wall, forcing you put your action-puzzle skills to the test without the luxury of stopping to plan your next move.
What really makes Warrior Within stand apart though is the fiendishly clever layout of the game. While both The Sands of Time and The Two Thrones have you following a generally straight-line path from point A to point B (granted, one that frequently involves climbing the walls and zigzagging through the more open sections), any given area in Warrior Within is going to be revisited two or three times over the course of the game. Aside from the aforementioned time travelling gimmick, the player's path very often involves leaving a room through a standard exit on the ground floor, loop around to find yourself looking down on that very room as you navigate the scaffolding above an hour later, then later still return to climb through the wreckage after our monstrous friend has drastically altered the landscape. There's also a real choice or two of where to go next, for those looking for a more traditional sort of complex exploration.
After Warrior Within, the PoP team moved on to The Two Thrones, which was largely an attempt at combining the best of both worlds between the previous two games. Sadly, rather than take the best aspects of each and amplify them, a few bad calls were made, and the rest suffered a bit of watering down. Warrior Within's complex layout is ditched for a return of the straight obvious path, while the darn fun combat regresses back to a more time consuming affair (in fairness, this is presumably to give extra incentive to use a newly introduced stealth kill system). The prince's snarky comments make a comeback, but he keeps the bulk of his newfound angst and guilt. Then of course we have some new gimmicks thrust on us, including a couple chariot race sequences which really just feel out of place, and the action genre's new best friend, Quick Time Events (you know, those things where a button sequence flashes on screen and you have to quickly punch it in). The Two Thrones also has a number of sequences where you transform into a half-monster with a stupid haircut and a shakeup to the mechanics which, while a nice change of pace, is a variation on a similar gimmick found late in Warrior Within that was implemented in a decidedly less frustration-prone manner.
This was followed by Assassin's Creed, a game which applies the same sort of exquisitely detailed wall scaling exploration to a truly open world. Unfortunately, so much of the developer's effort went into creating a set of three amazingly detailed cities to climb all over that they severely cut corners on everything else. The main goals of the game (sneak up on and stab 10 people), are broken up with roughly 30 optional side quests between each one. Unfortunately, these routinely consist of roughly 10 instances of "climb this building" 10 instances of "pick a fight with these guards" and a few mildly-less-repetitive but not particularly interesting goals, like killing 3 random guards in a few minutes, or sitting on a particular bench to watch a quick cut scene. The real tedium though comes from a frequently used and mind-numbingly dull combat system which generally boils down to holding down the block button, waiting to be attacked, hitting the counterattack button, and hoping for the roughly 50% chance of this causing an instant kill. On each of the dozen or so guards present. Shame that.