Games like Gravitas
Games like Gravitas include Portal, Portal 2, Helltaker, Poppy Playtime, and Human Fall Flat. We matched them by the tags players give Gravitas on Steam (Free to Play, Puzzle, Puzzle Platformer, Singleplayer, and Indie): closest matches first, and among equally close ones the better-known games.

Portal
Shared: Puzzle · Puzzle Platformer · Singleplayer

Portal 2
Shared: Puzzle · Singleplayer · First-Person

Helltaker
Shared: Free to Play · Puzzle · Indie

Poppy Playtime
Shared: Free to Play · Puzzle · Singleplayer

Human Fall Flat
Shared: Puzzle · Funny · Puzzle Platformer

A Story About My Uncle
Shared: Singleplayer · First-Person · Adventure

LIMBO
Shared: Puzzle Platformer · Puzzle · Indie

Viewfinder
Shared: Puzzle · Puzzle Platformer · Singleplayer

Halo Infinite
Shared: Free to Play · Singleplayer · First-Person

Hello Neighbor Alpha 4
Shared: Free to Play · Puzzle · Adventure

Supraland
Shared: Puzzle Platformer · Singleplayer · Puzzle

There Is No Game: Jam Edition 2015
Shared: Free to Play · Indie · Adventure

Samsara Room
Shared: Puzzle · Free to Play · Indie

Defy Gravity Extended
Shared: Puzzle Platformer · Puzzle · Indie

Little Nightmares
Shared: Singleplayer · Puzzle Platformer · Puzzle

Apex Legends™
Shared: Free to Play · First-Person · Adventure

Superliminal
Shared: Puzzle · First-Person · Singleplayer

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

Suicide Guy
Shared: Puzzle · Singleplayer · Funny

COCOON
Shared: Puzzle · Puzzle Platformer · Adventure

Deponia
Shared: Puzzle · Singleplayer · Adventure

The Stanley Parable
Shared: Indie · First-Person · Comedy

The Talos Principle
Shared: Puzzle · First-Person · Singleplayer

Polarity
Shared: Puzzle · Indie · First-Person