Here is the full list of all 38 Toki Tori achievements. It takes around 10-12 hours to unlock all of the achievements on Windows.
Finish all hard levels
Complete all Bubble Barrage hard levels
Collect all ten snowflakes that appear in December before they melt
Stand in the beam in Test Lab bonus level 2
Find her.
Stand in the beam in Test Lab bonus level 6
Complete all normal levels without using the Wildcard
Complete all Bubble Barrage normal levels
Complete all Test Lab normal levels
Watch the ending
Complete all Slimy Sewer hard levels
Collect 1000 eggs
Suck up 30 slugs
Complete all Slimy Sewer normal levels
Use 42 InstantRocks™ to finish a level
Complete all Creepy Castle hard levels
Find the Tunnel of Love
Trap 30 ghosts
Collect 500 eggs
Stand in all sun beams
Freeze 50 monsters
Trap Toki Tori between two Switchbricks
Finish a level without using all items
Complete all Creepy Castle normal levels
Telewarp directly into lava
Fall into the lava
Complete all Forest Falls hard levels
Collect 200 eggs
Use 32 bridges to finish a level
Press "Try Again" 10 times on one level
Make Toki Tori dizzy
Finish Forest Falls, Bonus 3
Play Toki Tori for 60 minutes without being idle for more than 2 minutes
Collect 100 eggs
Stand on an ice block for 12 seconds
Complete all Forest Falls normal levels
Get really close to a monster
Make Toki Tori look sad