# Thermo Sudoku — by Cracking the Cryptic > Sudoku puzzles with thermometer shapes and expert-crafted hints. (iPhone/iPad app by Nick Carney.) - Source: https://appshunter.io/ios/app/thermo-sudoku/id1513994223 (this page in markdown: same URL + `.md`) - Developer: [Nick Carney](https://appshunter.io/developer/1434235673) - Category: Games, Board, Puzzle - Price: $4.99 - Rating: 4.80/5 from 145 App Store ratings · 57 written reviews indexed - Age rating: 4+ - Requires: iOS 11.0 · 48 MB - Languages: American English - Released: 2020-05-20 - Data updated: 2026-09-04 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/thermo-sudoku/id1513994223/reviews.md ## What is Thermo Sudoku? ***** MARCH UPDATE ***** 20 new puzzles, 100 puzzles total! ------------------------------------- Presented by Cracking The Cryptic, YouTube’s most popular Sudoku channel, comes a new game featuring one of the most popular puzzle types: Thermo Sudoku. How does Thermo Sudoku work? Well each sudoku grid contains thermometer shapes (often drawn to create themes) and digits on thermometers must increase as one moves further from the bulb end. The interactions between the thermometers leads to new logical ideas and patterns that completely refreshes the standard sudoku solving experience. As with their other games (‘Classic Sudoku’, ‘Sandwich Sudoku’ and ‘Chess Sudoku’), Simon Anthony and Mark Goodliffe (the hosts of Cracking The Cryptic) have personally crafted the hints for the puzzles. So you know that every puzzle has been play-tested by a human being to ensure that the sudoku is interesting and fun to solve. In Cracking The Cryptic’s games, players start with zero stars and earn stars by solving puzzles. The more puzzles you solve, the more stars you earn and the more puzzles you get to play. Only the most dedicated (and cleverest) sudoku players will finish all the puzzles. Of course the difficulty is carefully calibrated to ensure lots of puzzles at every level (from easy through to extreme). Anyone familiar with their YouTube channel will know that Simon and Mark take pride in teaching viewers to be better solvers and, in these games, they always craft the puzzles with the mindset of trying to help solvers improve their skills. Mark and Simon have both represented the UK many times at the World Sudoku Championship and you can find more of their puzzles (and lots of others) on the internet’s biggest sudoku channel Cracking The Cryptic. Features: 100 beautiful puzzles Hints crafted by Simon and Mark! ## Key features - 100 unique puzzles - Thermometer logic - Expert-crafted hints - Progressive difficulty - Star-based progression ## Chart rankings - #69 in Top Paid · Board (US App Store) - #160 in Top Paid · Puzzle (US App Store) ## What do users think of Thermo Sudoku? Overall sentiment: mixed **Pros** - 👍 Well-made, challenging puzzles - 💡 Handcrafted, unique puzzles - 👍 Great logic and learning - 👍 Intuitive and beautiful interface - 👍 Excellent user experience - 👍 Hints explain logic, not just answers - 👍 Good for brain exercise - 👍 Smooth performance - 👍 Worth the price **Cons** - 🐛 Timer glitch/inaccurate tracking - 🐛 Awful controls - 🐛 Clues sometimes illogical - 🐛 Puzzles too hard/convoluted - 🐛 Locked puzzles behind easy ones - 🐛 Multiple solutions in puzzles - 🐛 Old menu design preferred - 🐛 Keyboard navigation incomplete - 🐛 Erase function unreliable - 🐛 Number pads too small - 🐛 Themes not ideal **Commonly reported bugs** - Timer adds incorrect hours/minutes - Timer adds 44 seconds when notifications are pulled down - Timer jumps when exiting/re-entering app - Wrong number put into box when leaving and loading app - Clues do not stand up to logic - Controls are bad - Erase function does not work as expected - Keyboard navigation incomplete - Arrow keys often don't register - Puzzle 24 impossible without cheating - Multiple solutions found in puzzles **Most requested features** - Fix timer glitch - Improve controls - Ensure logical clues - Add more puzzles - Unlock all puzzles - Improve hint clarity - Add synchronization across devices - Improve keyboard navigation - Add split view mode - Revert to old menu design - Allow reading hints while viewing board - Grey out used numbers - Improve erase function - Offer a theme similar to Chess Sudoku ## Recent user reviews (10 of 57) All indexed reviews: https://appshunter.io/ios/app/thermo-sudoku/id1513994223/reviews.md ### 4/5 — Nice Sudoku app (with one small flaw) *2024-01-26* While the app comes with “only” 100 Sudokus, all of them are very well made. Even the easy ones take a few minutes to solve and the hard ones may even keep you busy for an hour or more. I found the puzzles to be challenging but fair. My only complaint is, that with the latest app version running on iOS 17.2 the time tracking seems to be somewhat broken, sometimes adding hours to the recorded solve time. When locking the phone while a puzzle is open, chances are, that a few extra minutes will be added to the timer _after_ unlocking the phone (you can see the timer change in one big step). The difference is also much bigger than the time the phone was locked and can quickly add tens or hundreds of hours within a a few minutes. It seems to be somewhat dependent on the pre-lock value and not really linked to the lock time; the bigger the time the more time gets added. The highest change I observed was 980 added hours within a 5 second screen lock. Which is also why the app tells me, that it took me just over 40000 hours (4.5 years) to solve level #100, which was released less than two years ago… ### 4/5 — Timer glitch *2023-05-31* On iPhone, whenever playing a level on the screen if I bring down my notifications sliding down from the notch and then back up to return to the game, a 44 seconds gets added to the clock on the level; 100% of the time, same 44 seconds extra. Other than that great game. ### 2/5 — Awful controls *2023-05-05* The controls are so bad as to make it almost unplayable. Why not use the same number pad as Cracking the Crypto? If you fix this, i’ll change my rating to five stars. ### 5/5 — Brilliant *2022-09-14* Rich in customizable features and lovely, handcrafted puzzles :) Thanks for your efforts in creating these lovely apps, and the YouTube channel. ### 5/5 — Bug: Timing Error *2022-08-17* Great app, but sometimes when exiting and re-entering the app while solving the puzzle, the timer jumps, sometimes hundred of minutes at a time. I didn’t have this error on the Classic or Chess sudoku app. ### 2/5 — Starts out great but clues don’t make sense after a while *2022-04-05* This plies to all apps by the developer. When I get stuck on a puzzle and check the clues, it will say something like, “8 can only go in c7 in r2,” which doesn’t stand up to logic when it can clearly go in several other rows. I check it with someone else and they agree that the clue is wrong. It’s otherwise a good quality app, and the puzzles are mostly very good, but there are some glaring failures littered through the app. When the idea is to methodically solve a puzzle, it is frustrating when the next step defies all logic. There are several ‘logical leapfrogs’ across the series of apps. ### 1/5 — Haven’t followed through on promise *2022-03-01, version 1.3* Still waiting for the last 20 puzzles that were promised. Been at 80 for a while ### 1/5 — Broken Promise *2022-01-31, version 1.3* The app description says it will be enhanced to 100 puzzles within a year of introduction. It has now been over 20 months and we are still waiting. ### 5/5 — Love this app but 1 really annoying bug *2022-01-15, version 1.3* Love Cracking the Cryptic youtube channel so i had to get 1 of their apps. These puzzles are a lot of fun. My only issue is that there is 1 weird bug that can be quite annoying. Whenever you leave the app and load it back up, there is a wrong number put into box where you left off. Happens almost every time. Normally if this happens without resetting the app, you can just hit the undo button. ### 1/5 — App Falls Short on Promises *2021-10-24* It’s been well over a year and this app is still 20 puzzles short of the “100 puzzles within first year” promise upon launch. And, yet, the developers are releasing new games with similar promises. PLEASE keep your promises to people who bought your game at launch and release the remaining puzzles for this app. ## Frequently asked questions about Thermo Sudoku ### What is Thermo Sudoku? Thermo Sudoku is a variation of the classic Sudoku puzzle. It introduces thermometer shapes within the grid. Digits placed on these thermometers must strictly increase as you move away from the bulb end, adding a new layer of logic to the solving experience. ### How does the thermometer mechanic work? On a thermometer, the digit closest to the bulb is the smallest, and each subsequent digit further away must be larger. This rule interacts with standard Sudoku rules to create unique logical pathways and patterns for solvers to discover. ### Are the puzzles difficult? The puzzles are carefully calibrated to offer a range of difficulties, from easy to extreme. The goal is to provide engaging challenges for solvers of all skill levels, helping them improve their Sudoku abilities. ### Who created the puzzles and hints? The puzzles and hints were personally crafted by Simon Anthony and Mark Goodliffe, the hosts of the popular YouTube channel Cracking The Cryptic. They are experienced Sudoku players who have represented the UK at the World Sudoku Championship. ### How do I progress in the game? Players start with zero stars and earn them by solving puzzles. The more puzzles you solve, the more stars you accumulate, which in turn unlocks more puzzles to play. This system rewards dedicated and skilled solvers. ## Version history (last 5 releases) ### 1.4 — 2022-04-01 20 new puzzles, 100 puzzles total! ### 1.3 — 2021-03-31 20 new puzzles Smart hints (beta), computer generated hints that will help you enter in the next number Note: smart hints are not fully supported on all puzzles ### 1.2 — 2020-10-29 15 new puzzles Redesigned level select menu Added continue button to the home menu ### 1.1 — 2020-07-28 5 new puzzles QoL improvements New dark mode theme Manual save data sync option in the settings ### 1.0 — 2020-05-19 No release notes. ## Apps similar to Thermo Sudoku | App | Rating | Price | Category | | --- | --- | --- | --- | | [Sudoku: Variants & Classic](https://appshunter.io/ios/app/sudoku-variants-and-classic/id1530683853) | 4.8 (1,588) | Free | Games | | [Miracle Sudoku](https://appshunter.io/ios/app/miracle-sudoku/id1527363795) | 4.8 (117) | $4.99 | Games | | [Sumaddle](https://appshunter.io/ios/app/sumaddle/id1552172214) | 4.9 (766) | Free | Games | | [Sudoku Classic: Number Puzzles](https://appshunter.io/ios/app/sudoku-classic-number-puzzles/id6443815428) | 4.8 (382) | Free | Games | | [Killer Sudoku by Logic Wiz](https://appshunter.io/ios/app/killer-sudoku-by-logic-wiz/id1641151077) | 4.9 (188) | Free | Games | | [OneUpPuzzle](https://appshunter.io/ios/app/oneuppuzzle/id6504248356) | 3.8 (21) | $4.99 | Games | ## More apps by Nick Carney - [Achromatic!](https://appshunter.io/ios/app/achromatic/id1434235674) - [Sandwich Sudoku](https://appshunter.io/ios/app/sandwich-sudoku/id1476116705) - [Classic Sudoku!](https://appshunter.io/ios/app/classic-sudoku/id1488838275) - [Chess Sudoku](https://appshunter.io/ios/app/chess-sudoku/id1500654482) - [Miracle Sudoku](https://appshunter.io/ios/app/miracle-sudoku/id1527363795) All apps by Nick Carney: https://appshunter.io/developer/1434235673 ## Related topics [cracking the cryptic](https://appshunter.io/ios/topics/cracking-the-cryptic) --- *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 2026-09-04.*