1917 - The Alien Invasion DX achievements

Beat the game and unlock the Hard Mode

Kill the sixth Boss

Beat the complete game with the "SturmDecker" (In one sitting)

Playthrough without death. Become a true Bullet Hell Legend

Get a 666 Combo

Beat the complete game with the "FleischDecker" (in one sitting)

Playthrough with less than 10 deaths

Kill the fourth Boss

Kill the true final Boss