Here is the full list of all 26 Zenodyne R achievements.
Beat the game using the cameo ship!
Beat the game using the fifth ship
Beat the game using the fourth ship
Beat the game using the third ship
Beat the game using the second ship
Clear the Final Stage (Ending A)
Clear Final Stage Hard (Ending B!)
Beat the game using the first ship
Clear Stage 5 Hard
Clear Stage 4 Hard
Unlock unlimited credits!
Unlock all the lore!
Clear Stage 3 Hard
Unlock the Fifth Ship
Unlock all the ships!
Clear Stage 5
Clear Stage 4
Clear Stage 2 Hard
Unlock the Fourth Ship
Clear Stage 3
Unlock the Third Ship
Clear Stage 2
Unlock the Second Ship
Clear Stage 1 Hard
Clear Stage 1
Defeat the Commander (Ending C!)