Here is the full list of all 40 Indie Game Battle achievements.
Play a match in Turbo Mode.
Win a match as Salad Fingers.
Win a match as Dust.
Win a match as Teslakid.
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.
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 Gontaper.
Win a match as Electroman.
Win a match as Rex.
Win a match as Gip.
Win a match as Sol.
Win a match as Cal.
Win a match as Wizard.
Win a match as Huey.
Win a match as Chip.
Get 10 total KOs!
Win a match as Aria.
Win a match as Matt.
Win a match as Red Drop.
Win a match as Goat.
Win your first Survival match.
Win a match as Blue Blob.
Launch the game for the first time.
Get 100 total KOs.
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.