Here is the full list of all 44 Dallen Clicker Ultimate achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
First Time using Nuclear Clicker
Play as Ultimate Dallen
Collect 10,000 Dallen's.
First Time using Hyper Clicker
First Time Using Omega Clicker
Collect 1,000 Dallen's.
Collect 100 Dallen's.
First Time Using Ultra Clicker
First Time Using Auto Clicker
Collect Ten Dallen's.
Collect Three Dallen's.
Collect Four Dallen's.
Collect Five Dallen's.
Collect One Dallen.
Collect Two Dallen's.
Watch the entire intro cutscene.
Complete the game.
Collect 100,000 Dallen's.
Collect 1,000,000 Dallen's.
Play As Classic Dallen
Play as Dr. Dallen
Play As Nerd Dallen
Play as Cowboy Dallen
Play as Kingdom Dallen
Play as Karate Dallen
Play As F.B.I. Dallen
Play as Emo Dallen
Play as Dead Dallen
Play as Cool Dallen
Play As Demon Dallen
Play as Masked Dallen
Play As Anime Dallen
Play as Hooded Dallen
First Time using World Clicker
First Time using Galaxy Clicker
First Time using Universe Clicker
First Time Using Dark Matter Clicker
Viewed DLC
Watched The Credits
Play As Pyra Dallen
Play As Mythra Dallen
Play As Cranberry Dallen
Play As Fat Boy
Play As Brick Dallen