Here is the full list of all 40 Indie Game Battle achievements.
Play a match in Turbo Mode.
Win a match as Gontaper.
Win a match as Sol.
Win a match as Cal.
Win a match as Teslakid.
Win a match as Goat.
Win a match as Dust.
Win a match as Pico.
Win a match as Captain Viridian.
Win a match as Woodle Tree.
Win a match as NoLegs.
Win a match as Zee Tee.
Win a match as Red Drop.
Win a match as Artist.
Win a match as The Kid.
Win a match as Gip.
Win a match as Max & STEVE.
Win a match as Adventure Pals.
Win a match as Bingo.
Win a match as Jarvis.
Win a match as Wizard.
Win a match as Salad Fingers.
Win a match as Poncho.
Win a match as Rex.
Win a match as Electroman.
Win a match as Huey.
Win a match as Chip.
Get 100 total KOs.
Win a match as Aria.
Win a match as Matt.
Win a match as Blue Blob.
Get 10 total KOs!
Win your first Survival match.
Launch the game for the first time.
Get 500 total KOs.
Get 1000 total KOs.
Get 5000 total KOs.
Get 10000 total KOs.
Get 50000 total KOs.
Get 99999 total KOs. Wow, you deserve a cookie for this one.