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 Pico.
Win a match as Goat.
Win a match as Dust.
Win a match as Captain Viridian.
Win a match as Red Drop.
Win a match as Woodle Tree.
Win a match as NoLegs.
Win a match as Zee Tee.
Get 1000 total KOs.
Get 500 total KOs.
Win a match as Electroman.
Win a match as Adventure Pals.
Win a match as Chip.
Win a match as Gip.
Win a match as Matt.
Win a match as Huey.
Win a match as Blue Blob.
Win a match as Aria.
Win a match as Salad Fingers.
Win a match as Rex.
Win a match as Bingo.
Win a match as Artist.
Win a match as Jarvis.
Win a match as Max & STEVE.
Get 100 total KOs.
Win a match as Poncho.
Win a match as Wizard.
Win a match as The Kid.
Get 10 total KOs!
Win your first Survival match.
Launch the game for the first time.
Get 5000 total KOs.
Get 10000 total KOs.
Get 50000 total KOs.
Get 99999 total KOs. Wow, you deserve a cookie for this one.