Here is the full list of all 36 Highrise Heroes: Word Challenge achievements.
Link 6 survivors in a word
Meet the janitor
Make a palindrome with 5 or more letters
Play for 1 hour
Link 3 or more survivors in a word
Make 20 words with at least 6 letters
Get 3 stars on 20 levels
Make a 5+ letter word with more vowels than consonants
Make 100 words
Make an 8 letter word
Get a score of at least 35000
Complete a level within 30 seconds
Clear 1000 tiles
Read a character bio
Make a 6 letter word
Make a 7 letter word
Make a word containing 3 of the same letter
Complete the tutorial
Make a 5 letter word
Make a 9 letter word or longer
Make a word containing 4 or more of the same letter
Make a word containing 5 or more vowels
Spell a 6 letter fruit using only 3 different letters
Complete a level in the last second
Get a score of at least 50000
Make 1000 words
Make words beginning with each letter of the English alphabet
Spell every number from 1-9 in English
Form the secret 4 digit code in a numbers challenge
Play for 4 hours
Get 3 stars on every level
Collect every banana
Meet the nerd
Read all the character bios
Complete the game
Complete the game another way