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