You will find that the guest name easter eggs from 'RollerCoaster 1 and 2' will work on this game. Just rename a guest to the following listed name to unlock the corresponding effect.
Emma Garrell:
Changes the shirt color of every guest that passes her to purple
Lisa Stirling:
Constantly litters random trash
Eilidh Bell:
Decreases guest's happiness
Damon Hill:
Drives Go-Karts faster than normal
Jacques Villeneuve:
Drives Go-Karts faster than normal (though not as fast as Damon Hill or Michael Schumacher)
Michael Schumacher:
Drives Go-Karts faster than normal (though not as fast as Damon Hill)
Mr Bean:
Drives Go-Karts slower than normal
Felicity Anderson:
Every guest that passes her pukes
Nancy Stillwagon:
Gives ice cream cones to the guest standing next to her in queues
Mia Sheridan:
Increases guest's nausea
Joanne Barton:
Instantly carries a slice of pizza and some rubbish
Katie Rodger:
Instantly heads for the park's exit
Melanie Warn:
Instantly maxes out guest's happiness
Katie Smith:
Jumps up and down
Simon Foster:
Paints pictures of rides
Chris Sawyer:
Takes pictures of rides
David Ellis:
Thinks '... And here we are on (name of ride)!' when on a ride
Donald Macrae:
Thinks 'I'm lost!'
Elissa White:
Thinks 'I'm so excited - It's an Intamin ride!' when in a queue for a Giga Coaster
Andy Hine:
Thinks 'Nice ride! But not as good as the Phoenix...' after leaving a roller coaster
John Wardley:
Thinks 'Wow!'
Katie Brayshaw:
Waves
Tycoon Park
Beat every scenario in each group to unlock Tycoon Park. This is the large park featured on the title screen.