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