Clue Formula vs Popdoku
Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.
Clue Formula
Engage in a 3D Mahjong puzzle game featuring IQ-test style tiles. Match selectable pairs to clear levels, with increasing difficulty as you progress. Utilize hints and shuffles to aid your gameplay and compete on leaderboards.
- 3D Mahjong puzzle gameplay
- IQ-test style tiles
- Layered 3D levels
- Hint and shuffle options
- Leaderboard competition
- VoiceOver accessibility
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Clue Formula is a 3D Mahjong puzzle with IQ-test style tiles and pattern-matching challenges. Your goal is to complete all levels. In each level, remove all tiles by selecting matching pairs. Not every matching tile can be selected. A tile is selectable only when it is positioned at the end of a row - when there is no neighboring tile on at least one side (left or right) within the same layer. To complete a level, you need to find matching pairs where both tiles are selectable. Each new level becomes more challenging as you advance. A hint can show all selectable matching pairs. A shuffle can rearrange the remaining tiles and help you continue the level. Key Features: 3D Mahjong Puzzle: Match selectable pairs and clear each level. IQ-Test Style Tiles: Match tiles using shapes and symbols. Layered 3D Levels: Look through rows and layers to find selectable matching pairs. Leaderboards: Complete levels and compete for a place on the leaderboards. Accessibility and Device Support: Clue Formula is fully playable with VoiceOver. Clue Formula is fully supported on Mac. Extra hints and extra shuffles are available for purchase.
Popdoku
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Popdoku is a cozy logic puzzle where every number shapes the board. Read each bubble machine, plan colorful chains, and fill every open space to reveal the adorable animal waiting on the board. SIMPLE RULES, SATISFYING LOGIC Each machine shows exactly how many bubbles it must place. Drag up, down, left, or right to build straight chains. Bubbles cannot cross, overlap, or pass through another machine. Once a chain settles, your choice stays—plan ahead to avoid a dead end. DISCOVER 400 ADORABLE ANIMALS Every solved grid reveals one animal in full color and adds it to your collection. Meet familiar domestic animals through the main levels and discover friendly wild animals in the Daily Puzzle. A PUZZLE FOR EVERY BREAK • Explore 500 main levels • Return each day for a fresh Daily Puzzle • Use an optional hint when you need a nudge • Play without timers, at your own pace • Keep solving offline after installation Popdoku combines number puzzles, grid-based deduction, and animal collecting in one colorful brain teaser. Easy to learn, rewarding to master, and always ready when you want a thoughtful break. Read the numbers. Fill the grid. Discover every animal.
Screenshots
Verdict
The clearest difference is iOS requirement: Popdoku at 15.0 against Clue Formula's 17.0. On price, update cadence, ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Clue Formula sells 2 one-off in-app purchases and Popdoku sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
Both ship on a similar rhythm, roughly every 4 days. The most recent releases landed on October 25, 2026 and October 12, 2026 respectively.
| Parameter | Clue Formula | Popdoku |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (4 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 4 — better | — |
| Update frequency | Every 4 days | Every 4 days |
| Ads | Yes | Yes |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone, iPad, Mac | iPhone, iPad, iPod |
| Requires iOS | 17.0 | 15.0 — better |
| Further details — not scored | ||
| Size | 22 MB | 232 MB |
| Age rating | 4+ | 4+ |
| Developer | x2line.com LLC | 洋毓 曹 |
In-app purchases
Clue Formula
- Hint$0.99
- Shuffle$0.99
Popdoku
- Remove Ads$4.99









