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