# The Hamiltonian Circuit — A challenging puzzle game

> Grid-based puzzle game to find a continuous circuit visiting every square. (iPhone/iPad app by Good Thinking Games.)

- Source: https://appshunter.io/ios/app/the-hamiltonian-circuit/id1484345208 (this page in markdown: same URL + `.md`)
- Developer: [Good Thinking Games](https://appshunter.io/developer/1484345207)
- Category: Games, Puzzle
- Price: Free with in-app purchases
- Rating: 3.80/5 from 33 App Store ratings · 27 written reviews indexed
- Age rating: 4+
- Requires: iOS 16.6 · 64 MB
- Languages: American English
- Released: 2021-01-22
- Data updated: 2026-08-16
- Monetization: free with in-app purchases
- User reviews in markdown: https://appshunter.io/ios/app/the-hamiltonian-circuit/id1484345208/reviews.md

## What is The Hamiltonian Circuit?

Find a path that visits every square in the grid, avoiding walls and never crossing itself, to create one continuous circuit. 

To get the hang of things, start with one of the simple 4x4 grids. Plot your moves carefully. Try to think ahead; not just by one square, but by four or five. If you think you've made a mistake, trace back over your line. It will disappear.

If you really get stuck, press Hints. Any mistakes will turn red, then disappear. But if you're on the right path, we'll add a line.

There's only one solution for every puzzle. When you find it, you'll know.

Puzzles start with 4x4 grids and go all the way to 20x20. The bigger puzzles are very challenging and can take hours to solve. If you have to quit in the middle of one, don't worry: your progress is automatically saved. 

Many find working on these circuits meditative; others reach for the ibuprofen. But no matter which camp you find yourself in, know you're exercising your abstract thinking skills and challenging your brain in ways that actually matter.

Inspired by a puzzle created by Irish mathematician William Rowan Hamilton in 1856, these circuits start off easy and get hard. Really hard. Good luck!

Terms of use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

## Key features

- Visit every square on the grid
- Avoid walls and self-crossing
- Progressive grid sizes (4x4 to 20x20)
- Hint system for assistance
- Automatic progress saving
- Single solution per puzzle

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Pack of 50 Hints | $0.99 | one-time |
| Pack of 250 Hints | $3.99 | one-time |
| Unlock all puzzle packs | $18.99 | one-time |
| Unlock all puzzle packs | $30.99 | one-time |
| Basic Puzzle Pack 1 | $2.99 | one-time |
| Einstein mini-bundle 1 | $2.99 | one-time |
| Pack of 250 neurons | $3.99 | one-time |
| Pack of 750 neurons | $9.99 | one-time |
| Bright Mini 1 | $0.99 | one-time |
| Bright 1 | $2.99 | one-time |
| Sharp 1 | $2.99 | one-time |
| Pack of 50 neurons | $0.99 | one-time |
| Remove Ads | $4.99 | one-time |


## Recent user reviews (10 of 27)

All indexed reviews: https://appshunter.io/ios/app/the-hamiltonian-circuit/id1484345208/reviews.md

### 4/5 — Good puzzles!

*2024-10-03*

Started playing this after seeing the developer n Jeopardy.  The puzzles is great, and reminiscent of other circuit completion puzzles like Nikoli Slitherlink, and Kaser’s Willa’s Walk.

So why four stars?

The app itself feels like a minimum-viable product and could use a little more work. In particular, the lack of an undo/redo button is not great. I find myself having to hit reset if I paint myself into a corner and would prefer to tap undo a few times.  

Also when you start the app up, you have to do some menu diving to get to your last puzzle. This shouldn’t require more than a single tap.

**Developer response:** Great suggestions! We used to have undo/redo, but replaced it with pencil mode. I will seriously consider putting it back in. The comment about menu diving is right on the money, and I will definitely implement it. Glad you saw me on Jeopardy! Especially glad you shared your suggestions.

### 4/5 — Fun Game

*2024-09-27*

Would be 5 stars, but I can't seem to go back and re-play completed puzzles? I love the minimal interface.

**Developer response:** Good suggestion. I didn't think people would want to replay completed puzzles, but of course it makes sense.

### 4/5 — Gute Rätsel, wirkt aber noch unfertig

*2024-08-11*

Rätsel sind gut. 

Aber obwohl ich „Musik aus“ eingestellt habe, beginnt die Musik nach einem fertigen Rätsel wieder zu spielen und unterbricht das Hörbuch, dass ich hören will.

**Developer response:** Danke für den Bericht. Entschuldigung für meine langsame Antwort. Ich habe das Problem behoben.
David

### 5/5 — Addicting game

*2024-06-05*

Just downloaded this today and am already addicted!

**Developer response:** Thanks for the feedback! Let us know if you have any suggestions for improvements.

### 2/5 — Good game, but…

*2023-12-05*

A good, challenging puzzle game. But there’s no reason for it to run as hot or burn through my battery like it does. So what’s it doing in the background?

**Developer response:** Thanks for the feedback. We use profiling tools to measure energy consumption, as well as using the app on a variety of devices, and we haven't ever seen this behavior. If you get a chance, please send some additional information to info@goodthinkinggames.com. Let us know what device and model you're using, what version of iOS, and whether you notice the problem particularly when a particular screen is visible. Best, David

### 5/5 — Great game to keep you sharp

*2023-11-14, version 3.2.7*

I forgot about this game for a bit, after I got a new phone - but I do hope it is doing well l - as I am not getting back to it and getting addicted again! :)

### 1/5 — Fun game, 95% of it is behind a paywall

*2023-06-01, version 2.0.15*

Figured out how it works only to be confronted with a paywall to access the rest of the game and I can’t seem to replay any of the old levels

### 3/5 — Très bien, mais peu de contenu gratuit

*2022-08-11*

C’est un très bon jeu je trouve, stimulant c’est vraiment sympa, mais le jeu ne limite qu’à une catégorie sur 17, donc ça ne revient qu’à 50 puzzles, ce qui est trop peu. De plus impossible de refaire de précédents niveaux sans désinstaller l’appli

### 3/5 — Nice game, price too high

*2022-01-17*

It took me very little time to go through a set of problems I was charged for. Doesn’t make sense, and not in line with the cost of other games.

**Developer response:** Thanks for your feedback. We're committed to being a free app, but we do need some revenue! Stay tuned and we'll see what we can do.
Update: We've made all puzzles free, and introduced infrequent ads to make it feasible to continue to support the app.

### 5/5 — Great game but the scoring is confusing

*2021-12-26*

I love this game! Unfortunately I don’t understand how it’s scored. At the end of each level a percentage is given based on the number of grid spaces in the puzzle, however it’s unclear what the scoring criteria are.

Still worth every penny since it’s satisfying enough to solve the puzzles.

A very challenging game and nicely designed!

**Developer response:** The maximum score for a puzzle is based on the number of grid cells, as you noted. Depending on how hard the puzzle is, there's a time delay before the score starts going down. It's purely based on solving time.

## Frequently asked questions about The Hamiltonian Circuit

### What is the goal of The Hamiltonian Circuit?

The goal is to find a single, continuous path that visits every square on the grid exactly once, without crossing itself or passing through any walls. This creates a complete circuit.

### How does the hint system work?

If you get stuck, you can press the 'Hints' button. Mistakes you've made will turn red and then disappear, helping you identify errors. If you are on the right path, a line will be added to guide you.

### Is there a cost to play?

The application is free to download and play, but it does include in-app purchases and advertisements. Specific details on pricing for in-app purchases are not provided in the description.

### What kind of puzzles are available?

Puzzles start with simple 4x4 grids and increase in difficulty all the way up to very challenging 20x20 grids. Each puzzle has only one unique solution, and larger puzzles can take hours to solve.

### Can I save my progress on difficult puzzles?

Yes, your progress is automatically saved. This means you can quit in the middle of a challenging puzzle and return to it later without losing your work.

## Version history (last 5 releases)

### 3.5.0 — 2026-08-13

We fixed some omissions when counting achievements, and updated several components to the latest versions.

### 3.4.9 — 2026-08-05

We fixed a minor bug with hints not displaying right away, and updated all of our platform dependencies to the latest and greatest versions to improve stability.

### 3.4.8 — 2026-06-03

Routine platform and frameworks update

### 3.4.7 — 2026-03-04

Routine update for our platform.

### 3.4.6 — 2025-11-14

Updated platform components.

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## Related topics

[good thinking games](https://appshunter.io/ios/topics/good-thinking-games) · [abstract thinking](https://appshunter.io/ios/topics/abstract-thinking)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-16.*