Find Fred's basement workshop

Close a door

Pick up 15 things that don't belong to you

Create a cherry tree

Destroy a cherry tree

Open the safe

Make it rain

Pick up 30 things that don't belong to you

Play Maniac Mansion

Change the flag

Clothe Laverne in the costume

Hoagie eats a Hoagie

Get all six novelty items

Get a job

Deflate Oozo

Make vinegar

Climb through the chimney with all three kids

Enter the human contest

Microwave the frozen hamster

Wake up Dr. Fred

Red makes a super battery with only a little help from Hoagie

Make a skunk

Disqualify Harold

Get a tiny sweater

Win the human contest

Get Fred to sign the contract

Power Hoagie's Chron-o-John

Pick up 45 things that don't belong to you

Acquire a diamond

Power Laverne's Chron-o-John

Vacuum up a hamster

Defeat Purple Tentacle yesterday

Return the stamp album to Weird Ed

Play the whole game without skipping a cutscene

Sit through the end credits

Ask the IRS agents if they're related

Try to flush the hamster

Turn off the television

Try to mix the decaf and caffeinated coffees

Talk to Dead Cousin Ted with all three kids

Try to put something metal in the microwave

Try to mix the disappearing ink with Booboo-B-Gone

Try to microwave the hamster again after he's thawed out

Try to alter the contract with Booboo-B-Gone

Try to wash the dirty car with the brush

Squirt five different people with disappearing ink

Try to mix the red paint and the Booboo-B-Gone

Hoagie uses battery with Chron-o-John instead of plug

Try to swap the textbook with the stamp album

Laverne tries the chattering teeth on her human during the human show

Flush 50 objects through time

Try to sign the contract yourself with the quill pen

Ring the front desk bell 100 times

Laverne thinks about eating the cat

Talk to Washington, Jefferson, or Hancock while they're outside

Reach yesterday without turning the stereo off

Cook the hamster in Maniac Mansion (Don't try this at home, kids!)

Get all other achievements in the game