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