Zero/Sum vs Only One
Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.
Zero/Sum
Solve mathematical puzzles to uncover a cure for cancer in this unique puzzle game. Experience an 80s action movie-inspired storyline with live-action cinematics and a variety of fresh puzzle mechanics. Features daily challenges and time trials.
- Unique and original puzzle gameplay
- 80s action movie-inspired storyline
- Full motion video cinematics with real actors
- Variety of puzzle types (melting, number)
- Daily Challenge Mode with new puzzles
- Time Trial mode
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On the eve of discovering a mathematical cure for cancer, your mentor, Professor Claire Liddy, is murdered. Fortunately, before she died, the Professor was able to erase many of the plus and minus signs with her bloody hands, saving the cure from falling into the hands of her killers. Now it is up to you to fill back in the missing parts of the equation and resolve your professor's cure. It's up to you to cure cancer -- AGAIN! (It's a comedy). FEATURES - A completely UNIQUE and ORIGINAL puzzle game! - Puzzle gameplay that will make you feel and look SMART! - A thrilling, 80s ACTION MOVIE-inspired storyline! - Full motion video GREEN SCREEN cinematics! With REAL human ACTORS! - NO mention of CANDY or CUPCAKES or sweets of any kind in the story at all! - A variety of different puzzle types and mechanics to keep things FRESH (melting puzzles, number puzzles, and so much more)! - A Daily Challenge Mode featuring 10 NEW puzzles EVERY DAY! - Time Trial mode - try to beat your best time on RANDOM PUZZLES! - Completely INDEPENDENTLY developed and published! (Support your local punk band)! I ignored my newborn child to make this game, please ignore yours to play it!* *Note: I worked on the game every night after my son fell asleep, there is nothing more important to me than being a father. That being said, this game is a CLOSE second. Like neck and neck, really.
Only One
This is a minimalist logic puzzle game where each level requires you to find a unique solution related to the number one. Explore diverse puzzles and receive hints if you get stuck for over 45 seconds.
- Minimalist logic puzzles
- Unique solutions per level
- Theme based on the number one
- Variety of fun puzzles
- In-game hints after 45 seconds
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Let there be one! Only One is a minimal logic puzzle game where each level has it's own logic to be solved. Every level's solution has to do with something related to the number 1. One color? One piece? or even the number one itself. Just let it be one. Explore a variety of fun puzzles. And if in any case you get stuck on a level after 45 seconds a hint icon would be available to provide you with some help. Can you make it Only One?
Screenshots
Verdict
The clearest difference is review sentiment: Only One at 100% against Zero/Sum's 54%. Only One also leads on rating (5.0 vs 4.2). Zero/Sum's advantage is price (Free vs $0.99) and update cadence (every 2 months vs every 39 months). On ads, in-app purchases and device support 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
Zero/Sum is free to download; Only One costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Only One holds the better App Store score, 5.0 against 4.2. That said, the two scores are not equally well evidenced: Zero/Sum has 27 ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 54% of Zero/Sum's written reviews are positive against 100% of Only One's.
Zero/Sum ships an update every 2 months, Only One every 39 months. The most recent releases landed on October 26, 2026 and October 24, 2026 respectively.
| Parameter | Zero/Sum | Only One |
|---|---|---|
| Price | Free — better | $0.99 |
| Rating | 4.2 (27 ratings) | 5.0 (2 ratings) — better |
| Positive reviews | 53.8% of reviews | 100.0% of reviews — better |
| Number of ratings | 27 — better | 2 |
| Update frequency | Every 2 months — better | Every 39 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free — better | Paid |
| Devices | iPhone, iPad, iPod — better | iPhone, iPod |
| Requires iOS | 8.0 — better | 15.6 |
| Further details — not scored | ||
| Size | 973 MB | 65 MB |
| Age rating | 12+ | 4+ |
| Developer | Sean Kearney | Kofi Austin |
Customer experience
Zero/Sum
Only One
In-app purchases
Zero/Sum
No in-app purchases
Only One
No in-app purchases









