Here is the full list of all 26 Stardust Vanguards achievements.
Get a tri-kill.
Complete a round in "Stadium Epsilon."
Get a "Most Boring" post-battle status (have no other statuses).
Unlock all arenas, stadiums, and game modes.
Assassinate a VIP unit.
Complete all 30 survival waves in endurance mode.
Complete a round in the "Grid" arena.
Complete all 10 survival waves on medium difficulty.
Complete all 10 survival waves on hard difficulty.
Play a custom battle with insane amounts of reinforcements.
Lose an entire war to the pirates.
Play a custom battle with infinite ammo.
Deflect a bullet into another player.
Complete a round in the "Colony Attack" arena.
Play a match of Space Ball.
Get a "Sacrifice" post-battle status (your team won while you were eliminated).
The blue team wins a single battle.
The yellow team wins a single battle.
Complete all 10 survival waves on easy difficulty.
Call a 100 RP squadron into battle.
Complete a round of deathmatch.
Win a round while also being a bounty target.
Get a "Pyrrhic Victory" post-battle status (win with the most troop losses).
Get an "Honorable" post-battle status (never fire bullets).
The green team wins a single battle.
The red team wins a single battle.