Birthdays the Beginning's premise has a childlike simplicity: take a snowglobe world and fill it with life. No wonder: creator Yasuhiro Wada had the idea for the game as a child, after watching an episode of the cartoon Doraemon, which featured a tool to create a miniature planet, a mini-Earth that, once raised, could sit on a shelf in your bedroom while its ecosystem ticked away. Wada is best known for the series Harvest Moon, but while both games are bucolic enterprises exploring the stewardship of life, there is a vast difference in scale. In Harvest Moon you're a tinkering farmer; in Birthdays you're a sweeping divinity. Harvest Moon moves in seasons, Birthdays in millennia.
There's the whisper of a framing story, but this is a game in which the cogs and mechanisms of the ecosystem take centre stage. Your world, a kind of biodome encased in a cube of glass, is born small and flat. Your interactions are astoundingly limited: you can only raise or lower the land, which is divided into Minecraft-esque blocks. In this way, you have the power to build mounds, hills and mountains, or to dig puddles, lakes and seas. Life comes to the world first as a single cell plankton. When the right conditions are met, phytoplankton evolves into zooplantkton, and lo, the first link in the food chain is established. With time and careful tending, this fundamental principle is used to slowly and beguilingly fill your world with algae, ferns, trees, fish, spiders and, eventually, dinosaurs.
Evolution happens when the right conditions of temperature, moisture and terrain are met. The more water you swill into your cube-world, the higher the air temperature. The more dry land you raise, the lower the temperature. In this way you use erosion to fine-tune the environment in order to see your world flourish. Certain species of plant and wildlife will only evolve at certain temperatures, so the majority of your time is spent pruning the land, snipping off chunks of hill in order to trigger the emergence of some dinosaur, before filling in lakes and seas in order to lure another type, which will perhaps hunt the first creature. Evolutions will happen naturally, when the correct conditions are met, but it's also possible to hurry them along with dropped items, although doing so will usually lower your 'score' for the chapter.