Here is the full list of all 15 Bounty Battle achievements.
Complete Tournament For 7 Characters.
Complete Tournament For 14 Characters
Complete Tournament For 21 Characters
Complete Tournament For All Characters.
Finish tutorial.
Win a Battle in Gold Skin.
Win a Battle on Each Stage.
Win a Battle Using Each Character.
Eject 50 Opponents.
Win With a Bounty on You.
Finish a game with 100 Bounty points
Have a Bounty Put on You.
Defeat 1,000 opponents in versus mode.
Eject 1,000 opponents in local mode.
Unlock all skins.