Here is the full list of all 21 Rustbucket Rumble achievements.
While playing as Daisy, have 3 carry drones out at once.
Win a Ranked Match
While playing as Daisy, stun an enemy with your turret.
Complete a character tutorial
Get to level 25 in Ranked Matches
Get to level 50 in Ranked Matches
Play 50 games
Play a match with a friend
Watch the credits
Land the killing shot on El Rey Gigante Robo Jr.
Save an ally from being consumed by El Rey Gigante Robo Jr.
While playing as Clancy, heal an ally with less than 10% health
While playing as Clancy, heal yourself and 2 allies
While playing as Bjorn, absorb 100 damage with a single shield
While playing as Bjorn, stun 5 enemies that are carrying
While playing as Kasumi, stun someone and make it back to your recycler without being stunned
While playing as Kasumi, carry something at least 50 meters without using teleport
While playing as Valentina, stun someone who has been disabled
While playing as Valentina, grab something from max range
While playing as Maverick, hit 3 or more enemies with a single rocket
While playing as Maverick, use bombing run twice while carrying something