Here is the full list of all 19 Highway Blossoms achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
You know what you did
Started a new game
Got a copy of the miner's journal
Unlocked every journal entry
Tried out the hi-contrast textbox. Who knows, you might like it!
Turned on Goofball Mode
Set the character speed below 10 characters per second
Found the first piece of treasure
Didn't find the second piece of treasure
Let's hope you don't ever again
Finished the story
Finished the epilogue
Checked out the credits on your own time
Checked out the guest art section. Now all it needs is a glass case.
Turned on skip mode for all messages
Got lucky at blackjack
Now you're back on track
Completed Highway Blossoms on Extreme difficulty