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