Here is the full list of all 20 Hexodius achievements.
Achieve the story mode in Hardcore difficulty.
Travel to the 7th dimension.
Earn 500 credits in a bonus room.
Finish the Boss Rush mode.
Possess all the equipments and upgrades in Story mode.
Do 8 different bonus actions in an arena.
Do at least 10 multikill bonus actions during an arena.
Achieve the Story mode in any difficulty setting.
You have encountered all the basic enemy types of the game.
Travel to the 6th dimension.
Acquire 10 equipments and 10 upgrades in Story mode.
Complete 42 arenas in Story mode.
In Story mode, finish an arena with fully equipped B.O.B.
Possess 2000 credits in Story mode.
Perform your first dimensional travel.
Complete a world by finishing all the arenas in the Story mode.
Do a chain of 50 or more.
Obtain an S rank in any arena.
Obtain an A rank or better in all the Arcade rooms.
Discover all the bonus actions.