Here is the full list of all 34 BOMBFEST achievements worth 1,000 gamerscore. It takes around 2-3 hours to unlock all of the achievements on Xbox One.
Stick 2 Sticky Bombs to a single player
Play a full match in Uncomfortable Mode
Get a KO with a Rocket volleyed at least 2 times
Catch a falling Nuke
Survive when left with a single closed box in the Attic
Land in the bowl found in the Living Room
Catch Bread and throw it back at the original thrower
Catch and throw away a slomo'd bomb
Tilt the Big Duck to the side in the Bathroom
Remove the entire tower from the Nook
Have a player inside each wooden house in the Garden
Leap across the chasm on the Deck
Roll two 20s in a row on the Dicey Bomb
Unlock All Cosmetic Unlocks
KO a player holding a Cotton Sword with a Cotton Sword
KO another player into the waste basket in the Study
Clear the stage of blocks in the Dining Room
Steal first place from the wizard during the final round.
KO a player with a bomb they threw first
Unlock All Bombs and Stages
KO everyone with a single bomb
KO a player by pushing them into the toy car in the Toy Room
KO a player with a chain reaction involving at least 2 Potions Bombs
Play a round with all bombs disabled and no timer.
Fall down the drain in the Kitchen
Blast a player into a Button Mine's explosion
Play on the secret stage
KO someone from across the stage with a thrown Ice Bomb
Hit a single player 3 times with one Bouncy Bomb
KO 3 players with a single NON NUKE bomb
KO 2 players with a single NON NUKE bomb
KO a player through one of the outside walls in the Office
Get saved from an explosion by the train in the Bedroom
Self KO with the crown