The Warrior Within had a secret ending where the Prince defeats the Dahaka and the Empress survives. This game continues that version of events, and so the Prince returns to his home of Babylon with the Empress. They find it under attack by the Vizier who was defeated in the Sands of Time game. He is alive in this timeline because the Prince never defeated him and the Sands of Time weren't created. The Vizier has a plan to finish creating them by capturing the Empress. History repeats itself in some ways.
Even Farah is back and you run into her throughout the story. Instead of Farah going through cracks and you have to find a different path, now she just randomly runs through doors that always magically close. You never get to fight alongside Farah (when The Prince does, he only joins her in short cutscenes).
The Warrior Within had a very gritty approach to the aesthetics but now they have basically compromised on the style. The graphics are brighter, but yet it looks a bit washed out, but somehow a bit dark in places. I think there's some bugs with the lighting because some light sources are a mess, and it also has a weird bug where the screen goes white unless you tinker with some of the graphics settings. I encountered a few other glitches, mainly enemies falling through scenery.
The Prince looks fairly similar to his angsty Warrior Within style, but his original voice actor is back, so has a calmer demeanour and will talk to himself like he did in the first game. He also has a schizophrenic conversation with the "Dark Prince".
Near the end of the first game, the Prince became a Sand Wraith whose health depleted over time but was restored by sand. Once you were down to the last bit of health, the depletion stopped so you could only be killed in combat or traps. This game has the Dark Prince who you transform into at certain parts of the story. The Dark Prince's health depletes over time but does deplete fully so his sections play out like time trials. You need to look out for vases to smash which contain sand, or defeat enemies who will drop sand - this will restore your health. These sections end when you find a source of water, which is a similar idea to what stops the Dahaka. The Dark Prince has a whip which means in combat you have different moves. Navigation is different too where he uses his whip to extend wall runs, and pull out platforms.
The Prince has his usual parkour abilities, but now has some other moves. There's some spring mechanisms on the walls that allow diagonal jumps. There's dagger grip points to allow you to cling to walls. Chains and narrow walls to move up and down.
The game design is linear like The Sands of Time. You spend a long time in city areas and city buildings. I think the level design is the least organic out of the 3 games. In the previous games, there were definitely plenty of coincidences which allowed you to navigate the areas, but this seems even more blatant. For example, there's a corridor in a zigzag with a completely broken floor, but along the walls have the dagger grapple points.
The combat is similar to Warrior Within so you have a primary weapon and a temporary secondary weapon. The primary weapon is now your dagger. The weapons are temporary because they break quickly. This can make combat difficult since the dagger is very weak and stops you doing the high damage combos. So you will be scrambling to find a weapon rack or a fallen-enemies weapon. Most combat situations encourage you to avoid them completely with stealth-kills. These are triggered by Quick Time events. If there are clusters of enemies, you can take them all out with carefully chosen timing if you watch their patrol routes. There are some sections where enemies can spawn in if the alarm is triggered. Failing to take all enemies out in the stealthy way greatly increases the difficulty as you then need to take down several enemies in direct combat.
The Prince automatically moves in and out of stealth mode. When enemies can't see him, then he crouches. When he is detected, then he stands up. You can move fast in stealth mode anyway, it's more of a visual cue that you can stealth kill, or will fight normally.
You only need one button for the QTE's since Prince only uses his dagger. The dagger will flash and the action will slow down. I thought some of the timings of the QTE's were really short and some enemies take up to 5 button presses to successfully take-down. I was convinced that some flashes didn't appear. Many of the bosses rely on this mechanic and if you fail, you often need to repeat some tedious platforming or dodge attacks. I wasn't a fan of this at all.
There's a couple of Chariot Chases and one where you are riding a large beast. These involve moving left and right to dodge obstacles/walls whilst finding off enemies. The speed, and the narrow corridors often make this feel like trial-and-error rather than testing your reactions.
I criticised Warrior Within for not being obvious where to go sometimes. I felt Sands of Time did a great job at panning the camera to the next section but it wasn't as good in Warrior Within. Two Thrones does have the same problem which is frustrating when you are the Dark Prince and you are tested on time.
There were plenty of moments where I struggled to see where to go then noticed a switch on the wall. Often this seemed unnecessary to have the switch when it is right next to the door. These parts just seem like basic busywork and it doesn't help if it's placed slightly out of your eyeline or placed in the dark.
I wasn't impressed with the puzzle design either. Many I didn't understand the overall objective but since there is a crank, you may as well turn it. There was that statue puzzle which I assumed you had to get to the door to somehow smash the door, which was correct, but it was hard to see how to do that. You had one crank to rotate, and another to move forward, but it was hard to see why you wouldn't be able to move the statue forward due to the camera angles. Even when you get the prompt which allows you to zoom out the camera, you can't clearly see how much space you have and what would prevent the statue from turning, or moving forward. It mainly seemed trial-and-error but then was maddening that you had to cross over to the over side to get to the other crank. Why couldn't they just put the cranks right next to each other?
Some of the bosses had sections that were unclear like when you are battling the troll boss and he seems to stamp his feet which made me keep my distance, but he then has a one-hit KO move. You are supposed to get right into his stamping feet because it doesn't seem to damage you. The final boss had some inconsistencies where the first few attempts, I never saw him block and he didn't attack as frequently. Then there were moments where he would knock me down, I charge at him, he knocks me down, I charge at him, he knocks me down. But yet I could always attack him in previous attempts!? The final part of the final boss involves climbing up platforms and falling would mean instant death (unless you have sand tanks to rewind). But then he periodically hits you with a undodgeable projectile. If he hits you while jumping then there's nothing you can do. It just felt 100% trial and error.
I think you can draw some comparisons with the recent Star Wars trilogy. It almost seems like the 2nd game had new writers that took the Prince in a new direction then the 3rd game tries to undo part of the direction whilst introducing its own ideas. I actually thought the story was fine though. It was mainly the Quick Time Events and puzzles that could do with more thought.