Games like Cosmotronik
Games like Cosmotronik include ALTF4, Sonic Adventure 2, Portal, Portal 2, and Sonic Adventure DX. We matched them by the tags players give Cosmotronik on Steam (Action, 3D Platformer, Puzzle Platformer, Runner, and Platformer): closest matches first, and among equally close ones the better-known games.

ALTF4
Shared: Runner · 3D Platformer · Action

Sonic Adventure 2
Shared: Action · 3D Platformer · Platformer

Portal
Shared: Puzzle Platformer · 3D Platformer · Action

Portal 2
Shared: Platformer · Puzzle Platformer · 3D Platformer

Sonic Adventure DX
Shared: 3D Platformer · Platformer · Action

SONIC X SHADOW GENERATIONS
Shared: Action · 3D Platformer · Platformer

Sonic Frontiers
Shared: 3D Platformer · Action · 3D

Pseudoregalia
Shared: 3D Platformer · Platformer · 3D

Crash Bandicoot™ 4: It’s About Time
Shared: Action · 3D Platformer · Platformer

Defy Gravity Extended
Shared: Puzzle Platformer · Platformer · Action

Spark the Electric Jester 3
Shared: 3D Platformer · Action · 3D

SpongeBob SquarePants: Titans of the Tide
Shared: 3D Platformer · Action · Platformer

Ratchet & Clank: Rift Apart
Shared: 3D Platformer · Action · Third Person

SpongeBob SquarePants: The Cosmic Shake
Shared: 3D Platformer · Action · Platformer

Mirror's Edge™ Catalyst
Shared: Runner · 3D Platformer · Action

Pumpkin Jack
Shared: Action · 3D Platformer · Third Person

Last Train Outta' Wormtown
Shared: Action · 3D Platformer · Platformer

Psychonauts
Shared: Action · Platformer · 3D Platformer

Trine 3: The Artifacts of Power
Shared: Puzzle Platformer · 3D Platformer · Action

Neon White
Shared: 3D Platformer · Action · Platformer

Chained Together
Shared: Platformer · Puzzle Platformer · 3D Platformer

Legacy of Kain™ Soul Reaver 1&2 Remastered
Shared: Action · Third Person · Platformer

Haste
Shared: 3D Platformer · Action · Runner

Spyro™ Reignited Trilogy
Shared: 3D Platformer · Action · Platformer