Theta and Paralldox on Worldlines

Theta and Paralldox on Worldlines

Released Feb 2026

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

97% positive · 298 reviews
Not yet
Released, but content still planned
High confidence
Content Planned
Not yet
Released, but content still planned
High confidence
Content Planned

Where to buy

Steam $7.99 $9.99 −20%
Can't confirm — worth a look
We couldn't confirm these stores carry this game.
Green Man Gaming Steam key Search IndieGala Steam key Search
Prices in USD, as listed by each store.
Buying through an affiliate store helps support the site

Evaluation

Theta and Paralldox on Worldlines launched on February 3, 2026 as a complete 6-chapter puzzle game. Since launch, developer XXela has been consistently active, shipping a steady stream of patches that include bug fixes, level redesigns, new "insight levels," quality-of-life features (undo/redo, color preview for buttons and gates), and level rearrangements in Chapter 5 (V1.1.0, July 6, 2026). In the October 1, 2026 update post (V1.1.1), the developer explicitly stated: "A larger update is coming soon, featuring hints for Chapter 5 and more quality-of-life improvements." This is a clear, recent developer announcement of forthcoming content. The most recent post on October 7, 2026 (V1.1.3) continues the pattern of active maintenance. No unreleased DLC is listed on the store, and the announced update has not yet shipped.
Evidence
Developer explicitly stated 'A larger update is coming soon, featuring hints for Chapter 5 and more quality-of-life improvements.'
news post · Oct 1, 2026 source content planned
high
Game launched on February 3, 2026 as a complete product with 6 main chapters.
news post · Feb 4, 2026 source content shipped
high

Media

Details

Developer
Publisher
XXela
Achievements
28
Platform
Windows
Controller
full support
Steam Deck
Playable
Players
Single-player

About this game

  • Theta is a little girl who turns left every time she hits a wall. She is curious about the sinking world and discovers a mysterious place, where she picked up a fork that can split her into multiple copies of herself, and from that moment, the world changes forever.

  • Use the power of splitting to solve puzzles! Split yourself, the universe and something even vaster...

  • The game has 6 main chapters, each revealing at least one hidden truth that already hides within the core mechanics of the game from the beginning. Paralldoxs are under your nose!

  • By experiencing some abstract interpretations of modern physics, you will uncover the creation and operation of parallel worlds and other rules.

  • 240+ handcrafted puzzles, along with meta puzzles and hidden shiny collections that requires power of changing the world.

  • HInt system and Notebook : You can look up the knowledge you've learnt, or think about the essence of current level in Theta's dream.

  • Relaxing Graphics. Sit down and take a rest if you're tired. (Even in darkest places!)

Click "Add To Wishlist"!

Official Discord:

Last evaluated Oct 7, 2026
Something about this evaluation looks wrong Report illegal or harmful content