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