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