Screenshots
Watch trailer on Steam ↗Theta and Paralldox on Worldlines
XXela · Published by XXela, Delta Theta · Official site ↗
Very Positive — 98% positive (286 reviews) · 28 achievements
Last updated 29 Sept 2026
A lovely logical puzzle game about the many-worlds interpretation and quantum mechanics.
£7.65
£8.50Lowest price we've ever recorded
View on SteamPrices can lag the live Steam store — always confirm before buying.
Price history
Indie · 2026 · More £5 - £15 games
Explore the many-worlds interpretation by making decisions that ripple across parallel universes in Theta and Paralldox on Worldlines, an indie game from XXela released in 2026.
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:
System Requirements
Will my PC run this? →Minimum
- Requires a 64-bit processor and operating system
- OS: Windows 10/11
- Memory: 4 GB RAM
- Storage: 200 MB available space
Recommended
- Requires a 64-bit processor and operating system
Supported Languages
Latest news
Patch NotesOfficial
V1.1.0 Update
Remove levels 5-7 5-8 5-22 in old version， Rearrange the order of levels between 5-7 to 5-17 Add new level 5-20 Virtual Image Change level current5-8, 6-14，6-17 Fix Sliding on ice and stop by the box near the wall will still idle for one turn Fix Result when independent 2D conflicts with different axis happens at same timeRead full article on Community Announcements (xexlax)Patch NotesOfficial
V1.0.9 Patch #1
In the previous update, due to an oversight, levels 1-10, 1-11, and 1-14 accidentally reverted to an earlier version. They have now been restored to their correct state. Sincerely apologize for the inconvenience!Read full article on Community Announcements (xexlax)Patch NotesOfficial
Update V1.0.9
Added new level 3-9 (The previous 3-14 has been renumbered to 3-A; previous 3-9 to 3-13 have been shifted forward accordingly) Slightly adjust level 1-13, 3-21, and 5-4Read full article on Community Announcements (xexlax)Patch NotesOfficial
V1.0.8 Update
Fix UI Adaption in some resolution Now accept undo button(Z/GamePad B) to back in menus Fix a missed noteRead full article on Community Announcements (xexlax)Patch NotesOfficial
Patch V0.0.7 #2
Fix translation mistakesRead full article on Community Announcements (xexlax)
