Report updated May 4, 2026
Fill Shikaku
For casual mobile gamers interested in logic-based puzzles and grid-style brain teasers.
Fill Shikaku is a challenged games app that is free with in-app purchases. With a 4.3/5 rating from 6.2K reviews, it faces significant user friction. Users particularly appreciate core puzzle mechanics provide a satisfying and challenging brain training experience for casual players, though aggressive ad frequency and mid-level interruptions destroy the flow of the core puzzle experience remains a common concern.
What is Fill Shikaku?
Fill Shikaku is a grid-based logic puzzle game for mobile devices where users divide space into rectangular pieces.
Users hire the app for low-stakes mental stimulation, but the current ad-heavy experience forces them to abandon the puzzle-solving flow.
Current Momentum
v1.5 · 5mo ago
Zombie- Ships conformity updates and bug fixes
- Maintains stable store presence
Active Nemesis
100 Logic Games - Time Killers
By Andrea Sabbatini
Other Rivals
7-Day Rank Pulse 🇺🇸
GamesNo ranking data
Rating Pulse 🇺🇸
Recent User Mood
What makes this app unique?
What Does It Look Like?
What Are The Key Features?
Grid-based puzzle mechanic requiring users to divide space into rectangles and squares based on numerical constraints
Gesture-based control scheme for defining rectangular boundaries on the game grid
How much does it cost?
- Free with ad support
- In-app purchases for ad removal
Freemium model relies on ad-inventory for the majority of users, supplemented by in-app purchase conversion.
Who Built It?
Voodoo
Providing casual gamers with instant, satisfying entertainment through high-velocity, physics-based arcade and puzzle experiences.
Portfolio
13
Apps
What other apps does Voodoo make?
Explore the full Voodoo report
Portfolio breakdown, audience, momentum, and every app published by Voodoo.
What do users think recently?
High confidence · 99 reviews analyzed · Based on 99 reviews. Signal may be noisy.
How did the latest release land?
What is the recent mood?
Recent user voice shows a frustrated sentiment. Users appreciate core puzzle mechanics provide a satisfying and challenging brain training experience for casual players, but report aggressive ad frequency and mid-level interruptions destroy the flow of the core puzzle experience.
What Users Love
What Frustrates Users
View the full user-sentiment analysis
Mood gauge, ratings & review-volume history, every praise / complaint / request, and sentiment over time.
What is the competitive landscape for Fill Shikaku?
How's The Games Market?
Market outlook for this category
Available very soon
The rivals identified
Nemeses(1)
Offers a comprehensive suite of logic puzzles including Shikaku, directly competing for the same puzzle-solving audience.
Differentiators
- Bundles 100 distinct puzzle types into a single app, providing significantly higher long-term content variety.
- Focuses on a minimalist, utility-first interface that prioritizes rapid puzzle iteration over thematic visual flair.
Contenders(1)
Directly competes for the same grid-based puzzle demographic with high-frequency content updates.
Differentiators
- Implements spatial 'warp' mechanics that add a layer of complexity beyond standard grid-filling puzzles.
- Leverages a proven, high-retention visual language consistent with the broader Flow Free franchise ecosystem.
Same space(2)
Shares the 'number-to-grid' logic mechanic, serving as a primary alternative for grid-based puzzle enthusiasts.
Differentiators
- Utilizes a highly polished, thematic aesthetic that transforms abstract logic into recognizable pixel art.
- Features a robust progression system with seasonal events that drive daily active user retention.
Dominates the broader puzzle category, capturing the same casual logic-game player base.
Differentiators
- Offers advanced solver tools and automated hint systems that reduce friction for casual players.
- Maintains a massive, evergreen content library that keeps users engaged through daily challenge cycles.
New entrants(2)
High update frequency indicates a focus on content expansion and educational puzzle depth.
Differentiators
- Positions puzzles as educational brain-training tools rather than just casual time-killers.
- Integrates complex deductive reasoning paths that appeal to power users seeking higher difficulty.
Aggressive release cadence suggests rapid iteration and testing of new engagement mechanics.
Differentiators
- Employs a simplified 'match-and-clear' mechanic that lowers the barrier to entry for casual users.
- Rapidly shipping feature updates every month to optimize the user onboarding and tutorial flow.
Compare Fill Shikaku against every rival
All rivals in one side-by-side table — identity, store metrics, ratings & sentiment, and strategic intel — plus a head-to-head page for each.
The outtake for Fill Shikaku
Strengths to defend, gaps to attack
Core Strengths
- Core puzzle logic provides high-frequency session potential
- Gesture-based input lowers the barrier to entry
Critical Frictions
- Ad-removal IAP failure reported in reviews
- Aggressive ad frequency during active gameplay
- Technical instability in ad-delivery modules
Growth Levers
- Implement seasonal puzzle events to drive retention
- Introduce tiered difficulty levels to expand player base
Market Threats
- 100 Logic Games content variety
- Rapid iteration cycles from newer puzzle entrants
- Negative sentiment drag on new user acquisition
What are the next best moves?
Audit ad-removal IAP logic because users report persistent ads after purchase → reduce churn
Ad-removal IAP failure is a top-cited complaint theme in sentiment analysis.
Trade-off: Pause new level design sprints — fixing purchase reliability is a prerequisite for monetization.
Shift ad frequency to post-level screens because mid-level interruptions destroy flow → improve retention
Sentiment analysis identifies mid-level ad interruptions as the primary driver of negative reviews.
Trade-off: Accept lower short-term ad impressions — long-term retention gains offset the immediate inventory loss.
A counter-intuitive read
The app's high ad-frequency is not just a monetization choice but a structural failure, as it converts a high-retention logic puzzle into a disposable time-killer that users abandon at the first sign of friction.
Feature Gaps vs Competitors
- Multi-puzzle suite (available in 100 Logic Games but absent here)
- Seasonal progression events (available in Nonogram.com but absent here)
Key Takeaways
The app offers a solid core puzzle experience, but the aggressive ad-delivery and broken IAP logic are actively eroding the user base, so the PM must prioritize fixing the purchase flow and ad-timing to stabilize retention.
Where Is It Heading?
Declining
The casual puzzle market is consolidating around apps that balance monetization with a clean user experience, leaving Fill Shikaku exposed. If the team does not address the ad-removal failures and mid-level interruptions, the current negative sentiment trend will accelerate churn and permanently damage the app's store rating.
Technical failures in ad delivery force users to restart the app, which compounds the frustration of aggressive ad frequency.
Users report that paid ad-removal fails to function, creating a perception of deceptive business practices that drives uninstalls.