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 World Clicker
First Time using Nuclear Clicker
Collect 10,000 Dallen's.
First Time using Hyper Clicker
First Time Using Omega Clicker
Play as Ultimate Dallen
Play as Karate Dallen
Play As Demon Dallen
Play As F.B.I. Dallen
Play as Dr. Dallen
Collect 1,000 Dallen's.
Play as Emo Dallen
Play as Dead Dallen
Play As Nerd Dallen
Play as Cool Dallen
Play as Masked Dallen
Play As Anime Dallen
Play as Cowboy Dallen
Play as Hooded Dallen
Play As Classic Dallen
Play as Kingdom Dallen
Play As Brick Dallen
Play As Cranberry Dallen
Play As Fat Boy
Play As Mythra Dallen
Play As Pyra Dallen
Collect 100 Dallen's.
First Time Using Ultra Clicker
First Time Using Auto Clicker
Collect Ten Dallen's.
Collect Four Dallen's.
Collect Five Dallen's.
Collect Two Dallen's.
Collect Three Dallen's.
Collect One Dallen.
Watch the entire intro cutscene.
Watched The Credits
Viewed DLC
Complete the game.
Collect 100,000 Dallen's.
Collect 1,000,000 Dallen's.
First Time using Galaxy Clicker
First Time using Universe Clicker
First Time Using Dark Matter Clicker