Here is the full list of all 23 Zenohell achievements.
You are a shooting star.
Clear the game with Eonis Crystal (Continues allowed)
You are one among the elite of aces!
You killed the Zenonian Overlord!! (Stage 7 Clear)
You will DIE!
Clear the game with XOP Ultra (Continues allowed)
Clear ZOR mode (Continues allowed)
Clear the game with G85 (Continues allowed)
Clear KAI mode (Continues allowed)
You defeated the nasty boss rush mode!
Clear the game with EON (Continues allowed)
Clear the game with DRX-L (Continues allowed)
Clear the game with G90 (Continues allowed)
Clear ARC mode (Continues allowed)
You chose to turn back
You destroyed the multi-armament space station! (Stage 6 Clear)
everything before this, never mattered. (Stage 6 Boss Rush Reached)
The harder they fall! (Stage 5 Clear)
It was even more shiny when it exploded! (Stage 5 Midboss Clear)
The angry robot was no match for you. (Stage 4 Clear)
You destroyed the alien nuclear warmachine. (Stage 3 Clear)
Your home city was already in ruins when you arrived. (Stage 2 Clear)
You started the fight of your life! (Stage 1 Clear)