A bit difficult at times, but still a great game.
Sly Cooper and the Thievus Raccoonus is like your traditional platformer, but with one twist. It's also a stealth game. Yes, it sounds difficult to pull off, but Sucker Punch did it.
Sly Cooper is the last surviving member of a family of master thieves that pulled off many heists in the past. However, a gang called The Fiendish Five were responsible for killing Sly's father and stealing a book containing all of the Cooper family's journeys and skills called the Thievus Raccoonus. The gang is led by Clockwerk, who had a strong hatred for the Cooper family. The Fiendish Five split pieces of the book between them and disperse into their hideouts.
It's obviously Sly's main task to retrieve these pages and avenge his father's death. But he's not alone. With him are his companions, Bentley the turtle and Murray the hippopotamus. The three met at an orphanage when they were young and have been best friends ever since. The three of them have formed the Cooper Gang and they continue the Cooper family's legacy.
Sly is also "accompanied" by Inspector Carmelita Fox, an Interpol cop whose motive is to capture Sly and his friends for their heists. She follows the gang throughout the game and tries to arrest them, but the gang always outsmarts her. Sly takes a romantic interest in her, and teases her throughout the game whenever she shows up.
Back to the plot, Sly has to track down all of the Fiendish Five and take back the pages of the Thievus Raccoonus. Each member has retreated back into their hideout, which is sort of like a homeworld. Their are several independent levels in these homeworlds, which range from minigames or actual platforming levels. In each level, there are Clue Bottles. There's 30 in each level, and once you collect them all, you can open a safe at the end of level to learn a technique that one of Sly's ancestors knew.
Also at the end of each level is a key. These keys are used to unlock a lock keeping you from fighting the boss of that homeworld. The bosses are obviously members of the Fiendish Five. With that, there are five homeworlds in the game, with a boss at the end of each one.
The levels incorporate both platforming and stealth. The platforming is very similar to previous 3d platformers, like Spyro or Crash. There's not much to explain for this part, since we've seen it before. The stealth part is pretty cool though. In every level, there's some obstacles that would be harder to complete without the use of Sly's stealthiness. Things such as crawling under things, avoiding search lights, killing enemies from behind, sneaking on ledges, and much more. Both of these things together make the levels, and game itself, more unique and fun from other platformers.
The health system is pretty simple too. But, it's where the difficulty of the game ties in. Sly dies in one hit. That's irritating, I know, but you get used to it. There's also horseshoes you can collect that give you extra hits. You can only have a few of these on you at a time though. The game also runs a life system. You can sometimes find extra lives lying around, or you can collect coins. Getting coins is pretty easy. You can either find them on the ground, by killing enemies, or by simply smashing objects. Collecting 100 of them gifts you an extra live.
After beating a level, you always have an option of returning. So don't freak out if you a miss a clue bottle or two, you can always come back. There's also another reason to come back. Master Thief Sprints. These are a cool thing to do to keep you from being bored post-game. Once you reenter a beaten level, you can smash an hourglass at the start. You basically have to sprint your way to the end of the level, using your different abilities and skills. These can be quite difficult, but they are still fun to play.
With all that said and done, I think this game is definitely worth a purchase. The game does a superb job of telling the story and the characters themselves are charming. The platforming and stealth elements easily separate this game from any other platformer out there. With a great start like this, I don't think the Sly series will be leaving us any time soon.