I finished the game before the game changing updates, when the first update, which introduced the Gargantuars, was released I was able to play all the 3 gargantuar levels right away. After the latest update, which introduced the dr. Zomboss levels, I see the levels in all the worlds, but am able to play only the Egypt one. I finished it, yet I'm still unable to play the Pirate and Wild West dr. Zomboss levels.
How do I open those levels?
Best Answer
The past update was only for Dr. Zomboss on the Egyptian Level. Further updates (March 6th and 15th) made the boss fights on the Pirate Seas and Wild West levels available.
As can be seen in the PVZ wiki: