Here is the full list of all 40 Indie Game Battle achievements.
Get 100 total KOs.
Win a match as Woodle Tree.
Win a match as Pico.
Win a match as Gontaper.
Win a match as Zee Tee.
Win a match as Teslakid.
Win a match as Poncho.
Win a match as Captain Viridian.
Win a match as NoLegs.
Win a match as Dust.
Win a match as Bingo.
Win a match as The Kid.
Win a match as Gip.
Win a match as Electroman.
Win a match as Rex.
Win a match as Goat.
Win a match as Salad Fingers.
Win a match as Max & STEVE.
Win a match as Jarvis.
Win a match as Adventure Pals.
Win a match as Artist.
Win a match as Sol.
Win a match as Cal.
Win a match as Wizard.
Play a match in Turbo Mode.
Win a match as Huey.
Win a match as Chip.
Win a match as Aria.
Win a match as Matt.
Win a match as Red Drop.
Get 10 total KOs!
Win a match as Blue Blob.
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.