Bugsnax Achievement Checklist

Checklist

Catch your first Bugsnak. Unmissable. (Everybody Gets One)
Find your way to Snaxburg. Unmissable. (Gone Home)
Complete the main story of Bugsnax. Must have all side quests done. (Vacation's End / Survivor)
In Flavor Falls there are two waterfalls. The left waterfall contains a hidden passage; enter it. (Wonderfalls)
Steal Beffica's Diary from her cave after moving her to Snaxburg. (Perf Dirt)
Fully transform Floofy for her quest. (I'm Stuffed)
Upon getting Gramble to rejoin Snaxburg, stay up and in town around midnight and you'll notice Gramble sleepwalking. Feed him while he's sleepwalking. (Midnight Snak)
Watch all of Lizbert's video diaries. There are a total of five different video diaries that you can find and watch in Lizbert & Eggabell's house. (Documentarian)

#1 On the table in their home, right next to the projector.
#2 Lizbert's locked cabinet. Once you bring Beffica back to Snaxburg, interview her and she'll give you the key.
#3 Eggabell's locked trunk. Bring back Chandlo and Snorphy from Sugarpine woods and interview Chandlo for the key.
#4 Located in Sugarpine woods. Enter the area, take a right and follow the ridge to find a backpack, maps and this diary reel.
#5 Convince both Shelda and Floofty to return to Snaxbug. Shelda has a lockbox of Eggabell's, to which Floofty has the key. Interview both to unlock the box and find the final film reel.

Interview every Grumpus. You can check who you've interviewed in your journal. (Talkin' Bout Bugsnax)
Defeat all of the Legendary Bugsnax. They appear after certain side quests. (Bossy Bugs)

Return every Grumpus to Snaxburg. (Know Thy Neighbor)
Complete all 38 of the side quests. (Sidetracked)
Complete the adventure at Broken Tooth. This becomes available after completing side quests for Snorpy, Chandlo, Triffany, Floofty, and Shelda. (Deep Impact)

Use the Lunchpad to stun a flying Bugsnak by launching another Bugsnak at it. (Launch Party)
Stun a Bugsnak with the Trip Shot attached to your Buggy Ball. (Clothesline)
Catch more than one Bugsnak in your Snak Trap at once. (Double Trapper)
Catch 100 unique species of Bugsnax. You can check what you've caught in your journal. (Quartermaster / Halfway There / Got to Catch Them All)
Empty one biome of all its Snakpods. Below are the locations for Garden Grove. (Grab Bag)

Donate 36 Bugsnax to Gramble's ranch. (In The Arms of the Gramble)
Collect 10 hats. The hats come into play by viewing the board next to Gramble's Bugsnax sanctuary (attached to the side of his barn). Go to the area in the picture and capture the random Bugsnax wearing that hat. (Dapper Capper)

Scan a Grumpus after saucing them with cheese. (Say Cheese!)
Transform a Grumpus with Bunger, Fryder, and Sodie. (Combo Meal)
Transform a Grumpus with Scoopy, Banopper, and Cheery. (Sundae Best)
Fully transform every Grumpus (except Eggabell or Lizbert). (Feeding Frenzy)

Head over to the upper level where Cromdo was originally at and sleep until midnight, then look up at the three windmills. It may take a few nights. (Candid Cryptid)
Recruit Triffany, Gramble, Wiggle and then Chandlo and he'll build a starter house for you on the plot of land given to you. Equip a item for every possible slot in the hut. This is a long list - so visit ErickaUnlimited's original guide or this website's guide. (Live Laugh Hut)
Solve the secret of the lava cave or the secret of the dune. (That Reminds Me Of A Puzzle)

In the Boiling Bay, enter the lava cave and you'll see four statues against the far wall. Press them in the order (from left to right) 4,2,3,1 unlock this achievement and open up a shortcut to the Sizzlin' Sands.
For the puzzle in Sizzlin' Sands, activate the states the same way you did in the Lava Cave by pressing each statue in the order they are facing one another, with the fourth one being the last, as it is facing the secret entrance to the Boiling Bay.