ZERO_FILL

Click a tile, watch its neighbors shift, and try to bring an entire grid down to nothing. ZERO_FILL is a $1.99 game from developer Catoio Software, released 6 March 2026. This review draws on the game's full 2-review sample, unanimously positive.

A simple rule that gets genuinely deep

This review checked the store's own description alongside its sample and found the core mechanic consistently and clearly explained: clicking a numbered tile raises or lowers its value while also affecting its immediate neighbors, and the goal is to bring every tile on the board to zero within a limited number of moves. One reviewer described the concept as "a simple but surprisingly clever" hook that "quickly evolves into a thoughtful exercise in planning, pattern recognition, and strategic decision-making," specifically praising how the game forces players to think several moves ahead rather than relying on trial and error. The other reviewer echoed that read directly, describing 90 boards of "growing difficulty" and recommending the game specifically to players "into numerical puzzles."

Real content for a very low price

At $1.99, ZERO_FILL's feature list is worth spelling out plainly. This review checked the store's detailed description and confirmed a 75-board handcrafted campaign as the core offering, backed by a board creator that lets players build and share their own puzzles via share codes, plus an infinite random-board generator for use once the campaign is finished. That combination gives the game a real case for long-term engagement well beyond its low upfront cost, a point echoed directly by one reviewer's sample, who noted a "generator of random boards" becomes available once the base game's boards are cleared.

A difficulty curve reviewers specifically praised

This review's sample singles out pacing as a particular strength. One reviewer wrote that the game "balances accessibility and challenge" well, describing the basic objective as understandable "within moments," while later stages introduce enough complexity to keep experienced players engaged without becoming "overwhelmingly difficult too quickly." That same reviewer called the resulting learning curve "natural and carefully considered," language that reads as a specific, deliberate design compliment rather than generic praise.

A deliberately bare presentation

Neither reviewer treats ZERO_FILL's visuals as a selling point, and this review's evidence backs that read directly. One reviewer described the game's look as "very basic graphics (almost 80s aesthetics)," paired with "subdued but pleasant music." The other reviewer framed the same minimalism as a deliberate strength rather than a shortcoming, writing that the clean presentation "ensures that players can focus entirely on the puzzle mechanics without unnecessary distractions," and that the interface stays "straightforward and functional, making it easy to understand the state of each board at a glance." Shoppers expecting visual spectacle should look elsewhere, but this review's sample suggests that's a deliberate trade-off in service of the puzzle-solving itself, not a resourcing shortfall.

What the achievement data adds

This review checked the Steam achievement API and found a fairly gentle, gradual drop-off across seven tracked achievements: 90.9 percent of players earn a first-win achievement, dropping only to 51.5 percent for beating a randomly generated board, and settling around 21 to 24 percent for clearing later campaign worlds. That's a notably smoother curve than several other small puzzle and strategy titles this review has covered recently, and it corroborates this review's sample's praise for a difficulty curve that ramps gradually rather than spiking sharply. This review also checked the developer's partner-events feed and found a full campaign walkthrough posted the day after launch, a detail worth flagging directly, since it suggests at least some early players wanted help with the main campaign even if the broader achievement data doesn't point to a steep wall.

Accessibility options above average, with one notable gap

This review checked the store's accessibility feature-flag block directly and found seven of nineteen tracked flags true: color alternatives, camera comfort, mouse-only and touch-only control options, save-anytime support, a quicktime-event-free design, and a dedicated playable-at-your-own-pace flag. That's a stronger showing than most small-scale puzzle titles this review has covered this window. One clear gap stands out, though: no keyboard-only option is flagged, worth noting directly for players who rely on keyboard navigation, since ZERO_FILL's entire interaction model runs through clicking individual tiles.

A tag list that fits its own description

This review checked the store's own tag list against what this review's sample and description describe, and the match here is close and honest. "Puzzle," "Logic," "Minimalist," "Strategy," and "Level Editor" all track directly to features and design choices both reviewers explicitly describe. "Difficult" is a fair, if relative, description given the achievement data's drop toward the low twenties for later campaign worlds, and "Relaxing" fits the calm, distraction-free tone both reviewers praised even as the puzzles themselves grow more demanding. "Tutorial" is listed as a tag as well as being borne out directly by this review's sample, which describes an approachable, easy-to-grasp opening that builds gradually rather than throwing players into complexity immediately.

A quiet but tidy launch

This review checked the developer's partner-events feed in full and found a modest, tidy footprint: a pre-launch release-date announcement, the launch-day post itself, and the campaign walkthrough posted the following day, three posts total across a short, focused window rather than a long marketing runway. That's consistent with a small, solo-scale release rather than a heavily resourced launch, and it lines up with the game's own minimalist design philosophy, a developer putting its effort into the puzzles themselves rather than an extended promotional campaign.

Verdict

ZERO_FILL is a small, focused puzzle game that does exactly what it sets out to do, and does it well according to this review's unanimous, if very small, sample: a clever, easy-to-learn core mechanic that deepens meaningfully across a genuinely substantial 75-board campaign, backed by real replay value through its board creator and random generator. At $1.99, with a difficulty curve both reviewers specifically praised as fair and well-paced, this is an easy recommendation for logic-puzzle fans, tempered only by the thinness of the evidence available and a presentation that makes no attempt to be anything more than clean and functional.