The Steam version of myPOPGOES has many achievements to unlock.
These are very simple and easy to get with a couple of exceptions of course.
That being said, feel completely free to try and get all of these achievements!
This guide also contains some SPOILERS for the game, you have been warned!

“Beat Day 1 of the campaign mode.”
Beat Day 1.

“Beat Day 2 of the campaign mode.”
Beat Day 2.

“Beat Day 3 of the campaign mode.”
Beat Day 3.

“Beat Day 4 of the campaign mode.”
Beat Day 4.

“Beat Day 5 of the campaign mode.”
Beat Day 5.

“Collect all of Bonnie's diary entries via the Endless Day.”
Unlock the 3 diary entries by reaching 8:15 PM in Endless Day.

“Beat the Sticky Floor challenge.”
Beat the Sticky Floor challenge.

“Beat the Time Bombs challenge.”
Beat the Time Bombs challenge.

“Beat the Mini-Pizzas challenge.”
Beat the Mini-Pizzas challenge.

“Beat the Caffeinated challenge.”
Beat the Caffeinated challenge.

“Beat the Blind Resources challenge.”
Beat the Blind Resources challenge.

“Collect all of the stickers.”
Unlock the 24 stickers by beating both the campaign mode and all challenges.

“Beat the Fishing game.”
Beat the Fishing minigame.

“Beat the Topping Juggle game.”
Beat the Topping Juggle minigame.

“Beat the Longest Popgoes game.”
Beat the Longest Popgoes minigame.

“Beat the Pest Control game.”
Beat the Pest Control minigame.

“Beat the Whack a Rabbit game.”
Beat the Whack a Rabbit minigame.

“Collect all of the character sheets.”
Unlock the 5 character cartridges by completing all minigames.

“Reach the Normal Ending.”
Get the Normal Ending.
To get the Normal Ending, beat Day 5.

“Reach the Complete Ending.”
Get the Complete Ending.
To get the Complete Ending, reach 8:15 PM in Endless Day and beat all challenges and minigames.

“Reach the Secret Ending.”
Get the Secret Ending.
To get the Secret Ending, find the secrets in the minigames and then read the secret diary entry.

Fishing - Play until a wall on the bottom glitches and fish it to get the Balloon Boy head, then beat the minigame.
Topping Juggle - Spam the left button until you get the Toy Freddy head, then beat the minigame.
Longest Popgoes - Play until a wall on the left glitches and enter it to get the Toy Chica head, then beat the minigame.
Pest Control - Hold all buttons until the Mangle head appears and get it, then beat the minigame.
Whack a Rabbit - Wait until the rabbits get out of their holes and one of them will have the Toy Bonnie head, don't hit it and then beat the minigame.