Here is the full list of all 16 8-Bit Bayonetta achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Reach a score of 13000 or more
Kill a lot of angels
Finish with a very specific score
Dodge multiple axe attacks in 1 game
Launch the game multiple times
Single jump 30 times
Finish with a score between 8000 and 13000
Fire 1000 bullets
Reach a score of 5000
Double Jump lots during a game
Maintain a very high rate of fire
Die without scoring
Killed by a flying angel
Try again
Killed by a land angel
Kill a land angel