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.
Grab every item you possibly can.
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.
Gather all possible items dropped from the laundry chute.
Charge your cell phone.
Recreate a crime scene to get security off your scent.
Take pictures of every monster possible using the Haunted Camera.
Have your life ended in 10 unique ways.
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.
Access the mysterious dimension from every possible angle.
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.
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.