Patrick's Parabox
A mind-bending recursive puzzle game about boxes within boxes within boxes within boxes. Learn to use infinity to your advantage as you explore a deep and elegant system.
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Theta and Paralldox on Worldlines on Steam
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A lovely logical puzzle game about the many-worlds interpretation and quantum mechanics.
Theta and Paralldox on Worldlines is a puzzle, sokoban and logic game
developed by XXela
and published by XXela and Delta Theta.
Released on February 03rd 2026 is available on Windows, Steam Deck and Steam Machine
in 3 languages: English, Simplified Chinese and Japanese.
It has received 305 reviews of which 296 were positive and 9 were negative resulting in a rating of 8.9 out of 10. 😎
The game is currently priced at 9.75€ on Steam.
The Steam community has classified Theta and Paralldox on Worldlines into these genres:
Puzzle
Sokoban
Logic
Time Manipulation
Cute
Abstract
Surreal
Casual
3D
Singleplayer
Indie
Top-Down
Strategy
Difficult
Female Protagonist
Here is the detailed breakdown of supported languages for Theta and Paralldox on Worldlines:
| UI | Subtitle | Audio | |
|---|---|---|---|
| English | |||
| Simplified Chinese | |||
| Japanese |
Media & Screenshots
Get an in-depth look at Theta and Paralldox on Worldlines through various videos and screenshots.
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System requirements
These are the minimum specifications needed to play the game. For the best experience, we recommend that you verify them.
Windows
- Requires a 64-bit processor and operating system
- OS: Windows 10/11
- Memory: 4 GB RAM
- Storage: 200 MB available space
Steam Price & Best Deals
User reviews & Ratings
Explore reviews from Steam users sharing their experiences and what they love about the game.
Amazingly creative with its puzzles and by far one of the best (and hardest) puzzle games I’ve ever played, very rarely has a game consistently pushed my thinking this far and surprised me time and time again, keeping me hooked to the very end. At first, it may seem daunting controlling more than one character and understanding the movement rule, but as you play and get thrown into different scenarios these basics soon become second nature. And while this game is incredibly challenging, 99% of the time this difficulty comes from the logic required to find a solution rather than fiddly precise movements and placements – brute-forcing will very rarely help you or be needed, and if you find yourself just fiddling around without anything happening, it’s always better to take a step back and analyse the puzzle instead. My favourite aspect is how the mechanics of the world that have always been there are gradually revealed to you, while introductory levels in each chapter may bring them to your attention, there are plenty you can notice and discover early and you’ll soon be forced to discover small interactions and new ways to use rules on your own to progress. It’s very easy to feel as if something is impossible or that the same patterns you’ve relied on thus far suddenly aren’t working, and in these cases it’s often best to think outside the box or consider something new – clever thinking will constantly be rewarded, and your understanding will evolve not just because of explicitly new mechanics themselves, but the numerous ways you can use existing ones to interact with the world. The mechanics themselves are also brilliant with a fascinating quantum mechanics theming; the reveals are always great and each and every time had me thinking “that’s so cool!” Using them feels fun and intuitive too, as the game only layers on new mechanics after you’ve already proven your understanding of the previous ones in a variety of puzzle scenarios, so while your repertoire may be huge, you spend more than enough time in game using all of them to seamlessly integrate them into your puzzle-solving logic rather than spend too much time scouring your Notebook. Still, there’s nothing wrong with refreshing your knowledge from time to time, or simply trying something out and seeing what happens when you’re unsure or feel like you need something new, there’s a highly enjoyable blend of room for both logic and experimentation. Even by the end, puzzles will still have you thinking in ways you never have before, the game is incredibly long but manages to stay fresh the entire way through – in fact, even after all this I was so sad to see it finish! So, if you’re not hooked at the very start, I’d highly recommend sticking with it as it constantly outdoes itself and there’s so much more to this game than you could possibly imagine. And, if you’re ever completely stuck even after thinking for a good while, rather than just telling you a correct move, the “Gain Insight” feature on puzzles smartly gives you a separate mini-puzzle designed to demonstrate a way of thinking that may help you in the main one. However, I would always recommend thinking long and hard on puzzles first before seeking Insight or outside help, the magic of a good puzzle are those eureka moments where you finally realise what you were missing all along by your own thinking, after all. But, outside of a few required roadblocks, all puzzles are skippable, so feel free to do them in any order and come back later if your brain needs a break! However, if you skip too much and just beeline to the goal, you are prone to missing your introduction to certain concepts and may feel completely out of your depth on later stages, so I would still recommend doing as much as you can, or simply circling back when things start feeling too obtuse. The game very often iterates or plays with your understanding of a certain concept over a series of puzzles, so you would be doing yourself a disservice jumping all the way to the end. To top it all off, this game is visually beautiful, with a consistently striking use of colour themes and gradients mixed with simple but curious geometric shapes that gives the world a unique and mysterious feel. Theta herself is an absolutely adorable and endearing companion, I loved moving around as her and it was always a treat to hear what she had to say. Each Chapter also has its own pleasant, calming piano soundtrack as background music; I never got tired of them and they’re a more-than-fitting backdrop for the game’s puzzles and gorgeous aesthetic. If you’re up for a long, highly challenging, and creative puzzle game with a lot of depth to sink your teeth into, then please give Theta and Paralldox on Worldlines a chance and stick with it, it’s an absolute favourite of mine and I promise you won’t regret it.
While I've still got a good chunk of the game left to beat, I've played enough to confidently recommend it to others. It's a puzzle game based around a classic mechanic of clones, where you're controlling 2 or more characters at the same time, sharing inputs between both. However, instead of it being a throwaway mechanic to pad time, or just one of many mechanics that don't get fleshed out much, it makes this its core theme and goes all in. With a mechanic as inherently complex and intimidating as this, it's imperative that level design and curation be good. You want to show players cool stuff and not have them get lost in the complexity of the possibility space. The game does a great job at that, though for the first chapter of the game it might still feel a bit intimidating as you get used to its controls. It's sort of like Stephen's Sausage Roll in that respect, where the strange movement is something that you'll slowly get used to as you play, but the whole time the game is showing you new interesting wrinkles to the mechanics, and levels rarely feel like filler or difficult just for the sake of being difficult. Level difficulty is somewhat mid-high. I feel like it's roughly around Can of Wormholes difficulty. And like that game, this game also has a gain insight feature that helps guide you toward the realization when you're feeling stuck. Quite handy. There's some UX things that I wish could be nicer about the game, and some of the text could've used an editor, but overall it's very impressive and a very meaty brain teaser for puzzle game lovers. One of the best puzzle games in recent times. Solid recommend.
Theta overtook A Monster's Expedition as my favorite puzzle game of all time. I reached the first ending and finished all the numbered levels, and I want to continue and 100% the game. First of all, the theme and mechanics in this game is extremely unique. Controlling multiple characters is always going to be finicky, and even after I've finished the game, it is still finicky. However, very few if any of the levels that I've solved are reliant on difficult positioning of multiple characters. The prologue and first chapter is a bit like Stephen's Sausage Roll where you kind of have to suffer through the strange movement rules before you get to the actually interesting stuff. If you want to play this, you should be prepared to stay with it until you get to chapter 2. If you are in chapter 2 and it still is not fun, then the game is probably not for you. Every mechanic introduced is super interesting and more than justifies the jank from the base movement rules. Theta also inspired me to learn about quantum mechanics and the many worlds interpretation. The puzzle design is really good, on par with greats like Magicube, Stephen's Sausage Roll, and Snakebird. However, not ALL the puzzles are great. There are some levels (Chapter 6's Sword of Damocles in particular comes to mind) where the difficulty comes more from the constrained level space rather than the deductions required to come up with a solution. This is definitely the exception and not the norm, which is good. Now, my major criticism: the overall user experience of the game. The game feels unpolished. English translations are not good. Some things that I've noticed include: UI elements overlapping, or getting cut off at the edges of the screen (this was adjusted after I reported it in the Steam Discussions forum). The grid-based movement feels slightly off, not as smooth as other games. Sometimes I see light flashes across the screen, and I think it's the fork particle effect doing weird things. Sometimes the particle that the fork has is nice looking trail, other times it's a blocky orbiting rectangle. In chapter 3 and 6 specifically, the amount of timeline splits actually lags the game. One time in chapter 6, the lag persisted and I had to restart my game. However, I'm willing to deal with all this because the puzzle solving is just that much fun. According to the discussion forums, this game was AI-coded, but the puzzle design is definitely not. Without AI-coding I guess the alternative is that it wouldn't have been made into a game at all, which would be a shame. edit - per the dev's comment on this review, development was not reliant on AI coding. Will update my review upon 100% completion or True Ending :) edit - 100%'d the game. The post-game levels vary a lot in quality. 3-0 is controversial. I spotted the noise pretty easily. You could call it a red herring, and I can totally see players getting frustrated by it. My favorites would be the meta levels like 1-Z, 3-U, and the entirety of 0-U through 0-Z . The difficulty spike in post-game levels is extremely noticeable, barring a few exceptions that were solved within 5 minutes. Do I regret going for the 100%? No, but looking back on it, it hasn't heightened my enjoyment of the game. The regular game is overall way more fun mostly because of all the insane new mechanics introduced throughout. As a side note, I think that the difficulty of the post-game, and the difficulty of late Maxwell is beyond my enjoyment. The amount of time & effort I had to put in to solve these difficult levels was nowhere near the amount of dopamine I get when I eventually find the solution.
Beautiful puzzle game with many mechanical surprises. Many levels are "totally impossible and I can prove it!" until you figure out the trick. Most levels are simple and only have a few objects: it's a game about tricks and ideas, not about caseworking hundreds of combinations. (I hope the creator finds a way to include "negative probabilities," which is what makes the real-world Many-Worlds Interpretation so strange.)
Frankly speaking, you're only likely to come across this game if you're already into puzzle games. It's a trivial recommendation, so rather than praise it, it feels like it'd be best to give the few criticisms I have. Other reviews have already gone over the pros, that being the very inventive mechanics and clever puzzles which stays consistent throughout the game. Right off the bat, I feel the most comparable puzzle game to this is Stephen's Sausage Roll, but it's a lot more straightforward and direct with the puzzle layout at first glance. It eases you in rather than throws you into the deep end, but it is quite deep once you get going. Basically, each puzzle iterates the mechanics you already know then the next one asks you to do something new. There are very few repetitive puzzles, but sometimes the next puzzle is such a slight step it does feel like filler. At other times, the next puzzle feels like a giant leap that makes you feel completely lost not sure whether you're missing a mechanic, a trick to the mechanics, or are simply overlooking something obvious. The game has a mini-hint level system per level for the first couple of worlds which pretty much completely spells out the mechanic/trick the level is about, but it becomes absent more and more after the first couple of worlds. Thankfully level unlocks are based on simply seeing the previous level rather than beating them though there are some checkpoint levels which block your path until beaten. Overall, it's very similar to Stephen's Sausage Roll in that all the mechanics are there from the start, but it only gives you the opportunity to discover and play around with them as the game goes on and escalates. For the actual criticism. This is a game that is fiddly. You control multiple versions of the same character, Theta, the protagonist(this is spelled out from the first tutorial puzzle, so hopefully not too much of a spoiler) and there is no moving only one of them if you are controlling more than one in the same time. While a lot of puzzles try to be designed so this isn't a huge issue, it is still quite the issue. Especially when maneuvering things like boxes. Movement in this game is also designed that Theta automatically moves in the next available counter-clockwise direction if hitting a wall. Thetas that collide essentially merge and it is almost never desirable for two normal Thetas to merge as it functionally doesn't accomplish anything and puts you down a Theta. So you constantly have to reverse your actions when trying to maneuver Thetas around after accidentally merging them. You sort of get a sense of it, but 20 hours in and it's still not native to space them how I want when I need to and you need several types of specific positionings and orientations a lot due to the counter-clockwise thing and other mechanics dependent on her movement. Add not pushing boxes into walls/corners with errant Thetas and it gets very annoying. Very reminiscent of Baba puzzles which have you managing multiple characters and have them do things at the same time, but with even less intuitive wrangling due to the counter-clockwise movement thing. There are a couple of puzzles that really left a sore taste in my mouth due to it. Particularly the ones about maneuvering boxes in a 4-way junction. It's definitely something you can look past, but as this issue is fundamental to the game's movement at baseline, it never leaves. It is the one major caveat to the game and not one that can really ever be fixed as it's integral to many puzzles and the underlying system as a whole.
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Frequently Asked Questions
Theta and Paralldox on Worldlines is currently priced at 9.75€ on Steam.
No, Theta and Paralldox on Worldlines is currently not on sale. You can purchase it for 9.75€ on Steam.
Yes, Theta and Paralldox on Worldlines received 296 positive votes out of a total of 305 achieving a rating of 8.86.
😎
Theta and Paralldox on Worldlines was developed by XXela and published by XXela and Delta Theta.
Yes, Theta and Paralldox on Worldlines is playable and fully supported on Windows.
No, Theta and Paralldox on Worldlines is not playable on MacOS.
No, Theta and Paralldox on Worldlines is not playable on Linux.
Yes, Theta and Paralldox on Worldlines is playable on Steam Deck, though it might require a few minor tweaks. Make sure to check the Steam store page and community feedback on ProtonDB for exact compatibility details.
Yes, Theta and Paralldox on Worldlines is playable on Steam Machine, though it might require a few minor tweaks. Make sure to check the Steam store page and community feedback on ProtonDB for exact compatibility details.
No, Theta and Paralldox on Worldlines does not support VR.
Theta and Paralldox on Worldlines is a single-player game.
No, Theta and Paralldox on Worldlines does not currently offer any DLC.
No, Theta and Paralldox on Worldlines does not support mods via Steam Workshop.
No, Theta and Paralldox on Worldlines does not support Steam Remote Play.
Yes, Theta and Paralldox on Worldlines is enabled for Steam Family Sharing. This means you can share the game with authorized users from your Steam Library, allowing them to play it on their own accounts. For more details on how the feature works, you can read the original Steam Family Sharing announcement or visit the Steam Family Sharing user guide and FAQ page.
You can find solutions or submit a support ticket by visiting the Steam Support page for Theta and Paralldox on Worldlines.
Data sources
The information presented on this page is sourced from reliable APIs to ensure accuracy and relevance. We utilize the Steam API to gather data on game details, including titles, descriptions, prices, and user reviews. This allows us to provide you with the most up-to-date information directly from the Steam platform.
Additionally, we incorporate data from the SteamSpy API, which offers insights into game sales and player statistics. This helps us present a comprehensive view of each game's popularity and performance within the gaming community.
Last Updates| Steam data | 21 October 2026 21:03 UTC |
|---|---|
| SteamSpy data | 16 October 2026 15:13 UTC |
| Steam price | 22 October 2026 19:18 UTC |
| Steam reviews | 22 October 2026 05:45 UTC |
If you'd like to dive deeper into the details about Theta and Paralldox on Worldlines, we invite you to check out a few dedicated websites that offer extensive information and insights. These platforms provide valuable data, analysis, and user-generated reports to enhance your understanding of the game and its performance.
- SteamDB - A comprehensive database of everything on Steam about Theta and Paralldox on Worldlines
- SteamCharts - Analysis of Theta and Paralldox on Worldlines concurrent players on Steam
- ProtonDB - Crowdsourced reports on Linux and Steam Deck Theta and Paralldox on Worldlines compatibility
Game modes
Features
Online players
11
Developer
XXela
Publisher
XXela,
Delta Theta
Release
03 Feb 2026
Platforms