Here is the full list of all 90 Papa's Freezeria Deluxe achievements. It takes around 25-30 hours to unlock all of the achievements on Windows.
Serve 20 customers during Christmas wearing a Christmas Hat and Fur Parka
Earn 15 Gold Customer Awards
Use lots of musical furniture so 3 or more customers are dancing in the lobby
Add Cloudberries to Nevada's sundae
Add Shaved Mints to Edna's sundae
Serve a Truffle Bomb Special to Treble
Serve a Caramel Macchiato Special to Akari
Serve a Wildberry Moon Special to Willow
Serve a Sugarplum Streusel Special to Scooter
Serve all of the customers!
Dress your Chef and Driver in the exact same outfit but with different colors
Use Cotton Candy Syrup in Mandi's sundae
Serve a Cinnamon Crunch Special to Marty
Serve any 10 sundaes from the Food Truck
Serve a Vanilla Swizzle Special to Liezel
Earn 40 Special Recipes from customers
Add Pawpaw Topping to Papa Louie's sundae
Serve an Orange Roll Delight Special to Rollie
Serve everyone in the Romano Family Quartet
Send 10 Customer Coupons to your customers
Serve a Purple Pom Special to Pally
Use Yum n' Ms in Sasha's sundae
Serve all the band members of Scarlett and the Shakers
Have Quinn's order ready when she arrives and serve immediately
Serve Roy while wearing a Pizzeria Polo and Pizzeria Cap
Serve a Chocolate Creameo Special to Captain Cori
Lure 3 regular customers to the Food Truck by preparing their normal order
Serve the first customer last
Have Kahuna's order ready when he arrives and serve immediately
Have 10 different kinds of bubble gum in the lobby at once
Serve Jojo while wearing a Turtleneck and Beret
Serve a Red Velvet Cake Special to Kingsley
Unlock all of the Standard Mixables
Serve a Tropical Treat Special to Tony
Leave four sundaes on blenders at the end of the day
Serve a Mighty Mint Special to Mayor Mallow
Unlock all Volcano Gala toppings
Unlock all of the Standard Sauce Toppings
Reach Summer
Master 20 Special Recipes by earning 5 Stars on each
Unlock all Big Top Carnival toppings
Unlock all of the Standard Placeable Toppings
Unlock all of the Standard Mix Syrups
Unlock all Easter toppings
Unlock all St. Paddy's Day toppings
Reach Spring
Unlock all Valentine's Day toppings
Earn 10 Silver Customer Awards
Unlock all New Year toppings
Unlock all of the Standard Shakers
Unlock all Christmas toppings
Buy any 8 Posters from the Shop
Reach Winter
Master 10 Special Recipes by earning 5 Stars on each
Unlock all of the Standard Whipped Creams
Unlock all Thanksgiving toppings
Buy any 50 items from the Shop
Don't spend any money in the Shop for 7 days
Earn 15 Special Recipes from customers
Serve all of the Costumed Closers during Halloween
Unlock all Halloween toppings
Buy any 8 Furniture items from the Shop
Buy any 4 Flooring or Wallpaper from the Shop
Get 5 Blue Ribbons from Jojo the Food Critic
Serve 30 orders to customers in the Dining Room
Unlock all Maple Mornings toppings
Earn 15 Bronze Customer Awards
Buy all of the Upgrades in the Shop
Grab 250 coins while playing Papa's Raceway
Reach Autumn
Buy any 8 Clothing items from the Shop
Receive your wages on four Pay Days
Serve 100 customers while wearing clothing that matches the season
Win a Rare Bonus Prize in a Mini-Game by earning a Star Medal
Serve 20 delivery orders to customers
Unlock all Portallini Feast toppings
Earn 5 Bronze Customer Awards
Change your worker's shirt, pants, hat, jacket, and shoes.
Get a Perfect Score on 30 orders
Earn 5 Special Recipes from customers
Earn 5 Prizes or more in each of Foodini's Mini-Games
Get a 100% Topping Score on 20 orders
Unlock all Starlight Jubilee toppings
Wear a shirt, belt, jacket, pants, hat, and shoes to match the current holiday
Earn a Prize in each of Foodini's Mini-Games
Master a Special Recipe by earning 5 Special Stars
Get a 100% Build Score on 20 orders
Earn 3 Special Stars when serving Today's Special
Get a 100% Waiting Score on 20 orders
Get a 100% Mix Score on 20 orders