The Sapling

What the game is

The Sapling is an evolution and ecosystem simulator built by one Dutch developer, Wessel Stoop. It went into Early Access on Steam in December 2019 and is still there, which is the single most important thing to know before buying. It is PC only, single-player, listed in English alone, and Steam's own page warns that it can be glitchy and laggy.

You build a planet and then the life on it. The creature editor lets you design algae, plants, and aquatic, land and flying animals, choosing body parts, diet, reproduction, size and behavior. The world editor generates terrain, climate and up to eight seasons, and lets you trigger changes such as an ice age while the simulation is running.

There are two modes. Scenarios introduce the simulation a piece at a time, each setting a specific ecological requirement to meet. The sandbox unlocks everything and adds the feature Stoop considers the heart of the game: random mutations, which let evolution run on its own.

What you actually do

You make a species, place it, and press play. Then you watch. A plant specialized for low light spreads through a shaded valley. A predator you built to dive for fish drives its prey to extinction and starves. Populations rise, crash, and get replaced by something else that filled the gap faster.

The interesting work is diagnostic. Something dies out and you have to find why: too few of its food source, a season it cannot survive, a competitor doing the same job more cheaply. With mutations on you stop designing and start observing, watching traits you never chose appear because they happened to work.

What it exercises

• Explains why a species died out by tracing what it depended on.
• Predicts how a change in climate will affect a food chain.
• Designs an organism to fit a specific set of conditions.
• Watches a long process without intervening in it.
• Distinguishes a trait that was designed from one that emerged.

Why we rate it Moderate Worksheet score 59 / 100

1. FitHow much real knowledge or skill does the play itself make you use?58weight 45%

   Fifty-eight. Selection genuinely runs without the player's input, which is unusual and honest, but most of what a player does is set up conditions and then watch, which is closer to observing a real subject than working inside it. The scenario editor gives some hands-on design, though the simulation itself stays a spectacle.

2. TransferWill what you practise here work outside the game?50weight 30%

   Fifty. Watching an unplanned trait spread because it happened to work makes a genuinely difficult idea concrete, and that is real subject knowledge picked up by watching rather than being told. It stays in the middle of the range because the model is simplified and offers no vocabulary for what is being seen, so how much sticks depends on the player.

3. PracticeDoes the game make you use that skill again and again, as it gets harder?70weight 25%

   Seventy. The sandbox has no end state, so the design, run, observe and diagnose cycle repeats as long as a player stays interested, with a different planet each time and mutations that keep results unpredictable. It stops short of the highest band because the product is still unfinished, and its own instability can cut a long session short.

What the evidence says

Editorial onlyNobody outside our desk has checked this. It is our reading of how the game plays.

Editorial only. The Steam listing confirms the solo developer, the December 2019 Early Access release, the PC-only and English-only availability, the single-player structure, the creature and world editors, the scenario and sandbox modes, the random mutation feature, and the developer's own warning that the game can still be glitchy and laggy. It supports nothing about learning outcomes, and no study of this game exists. The claim about adaptation describes what the simulation makes visible, offered as editorial judgment about the mechanic rather than a measured result.

• The Sapling on Steam ↗ · Valve