Here is the full list of all 58 Day of the Tentacle Remastered achievements. It takes around 5-6 hours to unlock all of the achievements on Windows.
Get all other achievements in the game
Play the whole game without skipping a cutscene
Laverne tries the chattering teeth on her human during the human show
Try to sign the contract yourself with the quill pen
Squirt five different people with disappearing ink
Try to swap the textbook with the stamp album
Cook the hamster in Maniac Mansion (Don't try this at home, kids!)
Try to microwave the hamster again after he's thawed out
Try to mix the red paint and the Booboo-B-Gone
Laverne thinks about eating the cat
Try to mix the decaf and caffeinated coffees
Sit through the end credits
Defeat Purple Tentacle yesterday
Reach yesterday without turning the stereo off
Power Laverne's Chron-o-John
Vacuum up a hamster
Get a tiny sweater
Microwave the frozen hamster
Acquire a diamond
Return the stamp album to Weird Ed
Pick up 45 things that don't belong to you
Win the human contest
Disqualify Harold
Try to alter the contract with Booboo-B-Gone
Make a skunk
Deflate Oozo
Ask the IRS agents if they're related
Try to put something metal in the microwave
Ring the front desk bell 100 times
Flush 50 objects through time
Enter the human contest
Talk to Dead Cousin Ted with all three kids
Power Hoagie's Chron-o-John
Hoagie uses battery with Chron-o-John instead of plug
Red makes a super battery with only a little help from Hoagie
Make vinegar
Clothe Laverne in the costume
Get Fred to sign the contract
Talk to Washington, Jefferson, or Hancock while they're outside
Climb through the chimney with all three kids
Change the flag
Pick up 30 things that don't belong to you
Wake up Dr. Fred
Try to flush the hamster
Get a job
Try to wash the dirty car with the brush
Open the safe
Get all six novelty items
Try to mix the disappearing ink with Booboo-B-Gone
Turn off the television
Play Maniac Mansion
Pick up 15 things that don't belong to you
Destroy a cherry tree
Create a cherry tree
Make it rain
Close a door
Hoagie eats a Hoagie
Find Fred's basement workshop