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.
Kill a lot of angels
Finish with a score between 8000 and 13000
Die without scoring
Finish with a very specific score
Reach a score of 5000
Launch the game multiple times
Maintain a very high rate of fire
Fire 1000 bullets
Single jump 30 times
Dodge multiple axe attacks in 1 game
Double Jump lots during a game
Killed by a land angel
Try again
Killed by a flying angel
Kill a land angel
Reach a score of 13000 or more