Candy Crush Saga has 635 levels in Reality and 350 levels in Dreamworld. All these levels are divided into episodes. Each episode has a different story, mascot, and name. The episode name will have two (sometimes three) words (Polkapalooza is the only episode with one word). Some episodes have the same initials (e.g. Pastille Pyramid). There are currently a total of 43 episodes (seven Worlds: 6 episodes in each except World Eight) in Reality and 24 episodes in Dreamworld (four worlds: 6 episodes in each), with more to come.
The first two episodes contain 10 levels, the rest containing 15. At the end of each episode (starting with Candy Factory on Facebook, or Lemonade Lake on iOS and Android), to cross over to the next episode, you have to get three of your Facebook friends to give you a ticket to cross, or buy 3 gold bars (1 gold bar for each ticket). On Android or iOS, you can complete Mystery Quests (including three daily quests) to cross to the next episode if not synced with a Facebook account.
Each episode has its own mascot and special logo, too. The mascot is usually a person or an animal, or other things such as a robot, a vampire and even a fairy. The logo is usually the episode's name in bolded words with a background striped banner to match the episode's area.
On November 27, 2013, Dreamworld was released, with whole new episodes and levels. Each episode imitates the episode in reality, but usually in a more difficult manner. There are some exceptions though, e.g. Level 30 (Dreamworld). To get to Dreamworld, you have to click on an owl, Odus, on the map screen. Click on Odus again to return to Reality.
Here are all the current episodes in Candy Crush Saga:
Cupcake Forest - An episode that was added to the regular Candy Crush Wiki page by a vandal and spread to popular websites, leading to widespread beliefs. Would contain 7 jelly levels, 5 ingredient levels, 2 order levels, and a timed level; and would be Episode 30.