Many people have posted that they are having trouble unlocking all of the career star achievements. Often they have played out all of the career games, earning every star in each one, and still they do not have all of the achievements. This happened to myself as well. So they often wonder if this is a bug that never got fixed.

Is it a bug? Not really. The achievements can be done. It is a problem with the wording in their descriptions.

What the descriptions of the achievements does not tell you is, in order to get any one of the star achievements you must earn that star in a game BEFORE earning any other stars.

The Achievements are:

A Star is Born: Bronze Star
Rising Star: Silver Star
Brightest Star in the Sky: Gold Star
Star Studded Career: All

The "Creature Awakens" scenario is considered to be the easiest one to earn the achievements. This is because each star in that game requires you to hire 2 of a certain worker to get the star.

Bronze needs 2 Janitors
Silver needs 2 Mechanics
Gold needs 2 Entertainers

Begin a new game of "Creature Awakens"

Hire ONE of each worker.

Play the game out until you have completed all of the other requirements for that game's stars.
Bronze: Build 2 rides
Silver: Build 5 rides
Gold : Attract 1000 guests

Basically, you can build 4 Flat rides of your choosing, and connect their entrances and exits to paths to get up to Build 5 Rides requirement of the Silver Star. The Car ride "The Kraken's Lair" that the scenario comes with counts as one ride. After that, run the game until you have 1000 guests.

Save a copy of this game as it is. Before earning any stars.

Now hire enough of whichever worker is needed for a particular star.

When the game confirms you have met the requirements for the star, reload your saved game.

Hire the workers needed to get a different star.

Odds are, you already have the Bronze achievement so you should only need to reload the game once after hiring the workers needed for either the silver or gold star, whichever you choose to do first.

That's it.