Games like :3
Games like :3 include Celeste, Webbed, Planet of Lana, Öoo, and Portal 2. We matched them by the tags players give :3 on Steam (2D Platformer, Puzzle Platformer, Puzzle, Parkour, and Platformer): closest matches first, and among equally close ones the better-known games.

Celeste
Shared: 2D Platformer · Platformer · Female Protagonist

Webbed
Shared: 2D Platformer · Puzzle Platformer · Cute

Planet of Lana
Shared: Puzzle Platformer · 2D Platformer · Puzzle

Öoo
Shared: Puzzle Platformer · 2D Platformer · Puzzle

Portal 2
Shared: Puzzle · Platformer · Puzzle Platformer

LIMBO
Shared: Puzzle Platformer · Puzzle · Platformer

Braid
Shared: Puzzle Platformer · 2D Platformer · Puzzle

Portal
Shared: Puzzle Platformer · Puzzle · Female Protagonist

Defy Gravity Extended
Shared: Puzzle Platformer · Puzzle · Platformer

Trine 2: Complete Story
Shared: Puzzle Platformer · 2D Platformer · Platformer

Super Meat Boy
Shared: 2D Platformer · Platformer · 2D

ANIMAL WELL
Shared: Puzzle · Puzzle Platformer · Platformer

CATO: Buttered Cat
Shared: Puzzle Platformer · Puzzle · Cute

ElecHead
Shared: Puzzle Platformer · Puzzle · Platformer

The Pedestrian
Shared: Puzzle Platformer · Puzzle · 2D Platformer

FEZ
Shared: Puzzle · Platformer · Puzzle Platformer

Leap Year
Shared: 2D Platformer · Puzzle Platformer · Puzzle

Neva
Shared: Platformer · Puzzle · 2D Platformer

Mind Over Magnet
Shared: Puzzle Platformer · Puzzle · 2D Platformer

Momodora: Reverie Under The Moonlight
Shared: 2D Platformer · Female Protagonist · 2D

INSIDE
Shared: Puzzle Platformer · Puzzle · 2D Platformer

Out There Somewhere
Shared: Platformer · Puzzle · 2D

Katana ZERO
Shared: 2D Platformer · Platformer · 2D

Munin
Shared: Puzzle Platformer · Puzzle · 2D Platformer