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.
Beat the game with no weapon upgrades.
Reach the rank of Master Sergeant.
Reach the rank of Flight Lieutenant.
Reach the rank of Squadron Captain.
Reach the rank of Wing Commander.
Beat stage 5 in Burst Mode.
Complete the game in Burst Mode.
Beat stage 4 in Burst Mode.
Beat stage 3 in Burst Mode.
Beat stage 2 in Burst Mode.
Beat stage 5 in Classic Mode.
Complete the game in Classic Mode.
Beat stage 4 in Classic Mode.
Collect one billion points.
Beat stage 3 in Classic Mode.
Beat stage 2 in Classic Mode.
Collect 100 million points.
Beat stage 1 in Classic Mode.
Reach of rank of Sergeant.
Beat stage 1 in Burst Mode.
Collect one trillion points.
Defeat the True Boss.