Here is the full list of all 30 Sheepy: A Short Adventure achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
You finished the game without dying.
The last one?
You can do it!
You beat the game in 45 minutes.
You beat the game in 30 minutes.
Almost done!
... is awaiting you.
You finished the game.
You listened to all the tapes.
Wait, another Sheepy?
I know this place!
But now you can fly.
You showed Patches who's the boss.
Run as fast as you can.
GOTTA GO FAST
Archaeologist is a dangerous job.
The third one!
You have activated the 6 levers.
You lit all the crystals!
It feels nostalgic here.
BABY, RIGHT 'ROUND
Such an engineer.
The second one!
"Your estimated wait time is forever."
You made a new friend!
"Taking You Higher"
Something happened here...
The first one!
...but no you can't, because you're a sheep.
You're a smart one, aren't you ?