Games like Robbo Millennium
Games like Robbo Millennium include LIMBO, Is This Seat Taken?, Zup! S, Zup! F, and Braid. We matched them by the tags players give Robbo Millennium on Steam (Casual, Puzzle, Creature Collector, Puzzle Platformer, and 2D): closest matches first, and among equally close ones the better-known games.

LIMBO
Shared: Puzzle · Puzzle Platformer · 2D

Is This Seat Taken?
Shared: Casual · Puzzle · Logic

Zup! S
Shared: Casual · Puzzle · 2D

Zup! F
Shared: Casual · Puzzle · 2D

Braid
Shared: Puzzle · Puzzle Platformer · 2D

Baba Is You
Shared: Puzzle · 2D · Logic

Zup!
Shared: Casual · Puzzle · 2D

Defy Gravity Extended
Shared: Puzzle Platformer · Puzzle · 2D

Zup! 2
Shared: Casual · Puzzle · 2D

RetroMaze
Shared: Casual · Puzzle · 2D

Zup! X
Shared: Casual · Puzzle · 2D

Hook
Shared: Casual · Puzzle · 2D

Firework
Shared: Puzzle · 2D · Atmospheric

Scribblenauts Unlimited
Shared: Casual · Puzzle · 2D

Gorogoa
Shared: Puzzle · Casual · Atmospheric

A Little to the Left
Shared: Puzzle · Casual · 2D

Zup! 3
Shared: Casual · Puzzle · 2D

The Bridge
Shared: Puzzle Platformer · Puzzle · 2D

Zup! Z
Shared: Puzzle · Casual · 2D

Purple Place - Classic Games
Shared: Casual · Puzzle · 2D

Peggle Deluxe
Shared: Casual · Puzzle · 2D

Portal
Shared: Puzzle · Puzzle Platformer · Singleplayer

FEZ
Shared: Puzzle · Casual · Puzzle Platformer

Hexcells
Shared: Casual · Puzzle · Logic

