Here is the full list of all 56 Little Walker achievements.
Beat hard mode!
Beat the game without hitting 0 hp
Beat the game on auto-walk mode
Walk 500 more
Pop 99 balloons
Found moon mode... Oi.
HAPPY FEET, THAT AIN'T FALCO
Get 64 plusms
Discover that one place
Hi again!
Unlock 7 blocks
Talk to the funky seagull
Meet the moleman
Walk 500 miles
Squish the fly
Found the invisible block
You just have to keep eating food that's been sitting around, don't you?
Straight up robbed some dudes tomb
Beat the game on either mode
Read the sign you shouldn't have
Rode the golden dragon
Walked on the rainbow bridge
Felt the mighty power of the monoforce
Found spocker
Ran on hot coals for a while
Straight up murdered a majestic creature of the sky
Drank the very last swig that was just sittin there
Ring the bell above the abandoned mission
Enter the pyramid
Discovered the desert birds burrow
Dancing in the desert blowing up the sunshine
Conquered the cliff
Touched the apple wife (sadly she had apple-butt)
Kick a dude in the head
Straight up murder Carl
Jump 1000 times
Disturb the penguins
Found the legendary baby coin
Defeat 100 enemies
Found a shortcut
Discover the weirdos
Myup that was dookie
Went to the bathroom maybe?
Level up
Did the training room
Ate the trashcan sandwhich
Use the air breaks
Pick up the rock
Ate one of those red berries
Flipped the day/night switch
I hope you're proud of yourself
I get knocked down! but I get up again!
Fail to get back up
Get a plusm
Get spoken to by any character
Get an achievement