Here is the full list of all 25 Danmaku Unlimited 2 achievements.
Reach the rank of Ace.
Reach the rank of Colonel.
Reach the rank of Major.
Reach the rank of Wing Commander.
Beat stage 3 in Classic Mode.
Beat stage 2 in Classic Mode.
Beat stage 1 in Classic Mode.
Reach the rank of Squadron Captain.
Reach the rank of Flight Lieutenant.
Beat stage 4 in Burst Mode.
Collect 100 million points.
Reach the rank of Master Sergeant.
Reach of rank of Sergeant.
Beat stage 3 in Burst Mode.
Beat stage 2 in Burst Mode.
Beat stage 1 in Burst Mode.
Beat stage 4 in Classic Mode.
Beat stage 5 in Classic Mode.
Complete the game in Classic Mode.
Beat stage 5 in Burst Mode.
Complete the game in Burst Mode.
Beat the game with no weapon upgrades.
Collect one billion points.
Collect one trillion points.
Defeat the True Boss.