Here is the full list of all 40 Goosebumps: The Game achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Finish the game in # turns or fewer.
Complete the game after draining your phone to 0% battery.
Defeat Slappy while wearing the Haunted Mask.
Complete the game without ever using the cell phone.
Track down RL Stine in the phone book and give him a call.
Toss 10 expendable items into a deep, dark hole.
Grab every item you possibly can.
Gather all possible items dropped from the laundry chute.
Charge your cell phone.
Recreate a crime scene to get security off your scent.
Have your life ended in 10 unique ways.
Take pictures of every monster possible using the Haunted Camera.
Correctly answer a riddle as if your life depended on it.
Achieve a perfect game of skeeball.
Survive a power outage with gnome complications.
Pry the Haunted Mask off your face.
Be proactive and start your laundry.
Disable a deadly toy bent on destruction.
Take a photograph using the Haunted Camera.
Survive the game to completion.
Discover Slappy's secret shame.
Find entry into the bookstore.
Find a way to call RL Stine without touching gross coins or a dirty phone receiver.
Find a way inside the Mall.
Convince your brother to give you a ride across town.
Intimidate a very deadly creature.
Narrowly escape defeat by wearing a talisman into the woods.
Access the mysterious dimension from every possible angle.
Look into an antique mirror and do some self reflection.
Solve a compression problem to reach the attic.
Use modern technology to give the second Ghost Child his heart's desire.
See to the needs of the 3 unexpected guests.
Evict an elderly intruder.
Tell Aunt Dahlia about your weekend plans.
Face what lies beneath the sink... and survive!
Complete Area 1 and return home.
Place the Magician's Top Hat on its rightful owner.
Find a way past the strange man in the woods.
Collect the cell phone from your school locker.