Here is the full list of all 12 Solar Shifter EX achievements.
Meet Allen Volker for the first time.
Accomplish the first mission without taking damage.
Upgrade both weapons to level 2 when you're visiting the Shadow Hub for the first time.
Accomplish the second mission without taking damage.
Defeat the second Ardath Clan Boss.
Own 700 credits when arriving to a hangar.
Finish the game.
Fully upgrade both weapons.
Accomplish the third Astra Corps mission without taking damage.
Accomplish the last mission without taking damage.
Destroy the colony as the Alien Ravager.
Destroy Cloud City as the Alien Striker.