Here is the full list of all 48 Creekside Creep Invasion achievements.
You killed Frank
You made a super costume
You got the skateboard
You drank an Ice Gulp
You fully upgraded the mini-mart
You completed your first quest
Have all armor slots filled
You have 99 dollars
You completed downtown
You completed the suburbs
You completed the cemetery
You completed the carnival
You killed Skelly
You killed the Beast
You defeated Dr. Apollyon
You killed Sye Klops
You killed Dirty Rat
You killed Scarlet
You killed a Trash Mimic
You killed a Dumpster Mimic
You killed a Loot Goblin
You found the Sewer Shop
You entered a Danger Zone
You opened a Mystery Box
You swapped ammo
You won something from the Claw game
You have 99 dollars in the bank
You won some money in the Lotto
You repaired your armor
You drank a soda
You ate an ice cream
You beat the bottomless pit
You completed the Bottomless Pit without getting hit
You completed the Carnival without getting hit
You completed the Cemetery without getting hit
You completed the Suburbs without getting hit
You completed Downtown without gettting hit
You met Creepy Carl
You beat hard mode
You beat marathon mode
You beat marathon mode on hard
You killed a minion with a crate
You found a kitty friend
You unlocked all ammo types
You unlocked all the costumes
You killed carnie Frank
You killed carnie Skelly
You killed the carnie Creep