Theta and Paralldox on Worldlines

A lovely logical puzzle game about the many-worlds interpretation and quantum mechanics.

At a glance

• Platform: Windows.
• Genres: Indie.
• Release date: Feb 3, 2026.
• Steam user reviews: Very Positive (97% positive).
• Delivered as a Steam library entitlement — activation is handled by Steam.

Minimum

Recommended

System requirements as published by the developer on Steam.

Activate on Steam

• Open the offer above — it takes you to this game's official Steam store page.
• Buy it there, or if you bought a key elsewhere, open Steam and choose Games → Activate a Product on Steam.
• Enter the product code exactly as it was issued to you.
• The game appears in your Steam library — download and play.

CDKeyCheap does not sell keys. We track and display prices; every purchase happens on the store you click through to.