Here is the full list of all 13 Jash achievements.
The first Boss is defeated
You like Rice Wine Sake
You find one Easter egg!
The second Boss is defeated
You finished the light speed level
You found the hidden card
You finished the Top Down shooter levels
Another Easter egg unlocked!
The third Boss is defeated
A reference to a famous game
The fourth Boss is defeated
The game is finished!
A reference to a famous song