Games like Boris the Sloth
Games like Boris the Sloth include Human Fall Flat, LIMBO, Portal, Portal 2, and The Bridge. We matched them by the tags players give Boris the Sloth on Steam (Puzzle Platformer, Old School, Adventure, Nature, and Comedy): closest matches first, and among equally close ones the better-known games.

Human Fall Flat
Shared: Adventure · Puzzle · Puzzle Platformer

LIMBO
Shared: Puzzle Platformer · Puzzle · Adventure

Portal
Shared: Puzzle Platformer · Puzzle · Comedy

Portal 2
Shared: Puzzle Platformer · Puzzle · Adventure

The Bridge
Shared: Puzzle Platformer · Surreal · Puzzle

Planet of Lana
Shared: Puzzle Platformer · Puzzle · Adventure

Webbed
Shared: Puzzle Platformer · 2D Platformer · Adventure

Viewfinder
Shared: Puzzle Platformer · Puzzle · Adventure

The Pedestrian
Shared: Puzzle Platformer · Puzzle · Logic

Neva
Shared: Adventure · Puzzle · Nature

ANIMAL WELL
Shared: Puzzle Platformer · Puzzle · Adventure

Oddworld: New 'n' Tasty
Shared: Puzzle Platformer · Adventure · Puzzle

Murders on the Yangtze River
Shared: Adventure · Puzzle · Puzzle Platformer

Creaks
Shared: Puzzle Platformer · Puzzle · Surreal

Thank Goodness You're Here!
Shared: Adventure · Comedy · 2D Platformer

Mind Over Magnet
Shared: Puzzle Platformer · Adventure · Puzzle

Öoo
Shared: Puzzle Platformer · Puzzle · 2D Platformer

Little Nightmares
Shared: Adventure · Puzzle Platformer · Puzzle

There Is No Game: Wrong Dimension
Shared: Adventure · Puzzle · Comedy

Pikuniku
Shared: Adventure · Puzzle · Indie

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

Superliminal
Shared: Puzzle · Surreal · Adventure

Braid
Shared: Puzzle Platformer · Puzzle · 2D Platformer

The Cave
Shared: Adventure · Puzzle · Comedy