Here is the full list of all 19 GoNNER achievements.
You pushed that big piece of trash off your lawn. Good on you.
You hit the glyph cap!
You completed Shooty world! Smooth!
You completed the Robot world. Impressive.
These combos are just getting ridiculous...
You completed the Cave world. Good job.
It's not even ASCII, how can it even be called Roguelike???
You got a combo of 15!
You picked up a glyph!
You got a combo of 5
You became Death.
you found sally
You completed Death world! Woah!
I'm a serious adult person and I think this kind of humor is childish and should be banned.
I believe in you, get back up.
You jumped on 20 enemies in a row
There's nothing there! No easter egg, no extra item, no nothing. Just a dumb achievement.
Didn't have to skip death.
Did you just run out of colors?