Idle-builder · solo · Unity

Undergrowth

A mycorrhizal idle-builder prototype. You're a fungal network under burnt bushland: buy buildings, place them in the soil, and grow your network until you can awaken the Old Tree. I built the whole game on my own as a demo in Unity.

Role: Solo developer
Engine: Unity · C#
Year: 2026
Status: Prototype demo

Undergrowth gameplay: a green growth area spreading over dark soil, with buildings linked by lines back to the Heart Stump, a Root Tip's circle on a rich soil patch, a resource bar along the top, quests on the left and the building shop on the right — Placing a Root Tip on rich soil. Each building links itself to the network, and the game warns when one is placed too close to another.

Systems I built

Linking chains: every building you place links itself to the nearest building in reach, so the network visibly grows across the soil, and placement checks stop buildings being crammed too close together
The auto-upgrader: Weavers level up every building inside their circle for free, to one level below their own, and you spend enzymes to level the Weavers themselves
An economy of four resources: Root Tips draw nutrients (glowing soil patches are richer), Saplings trade nutrients for sugar, Spore Presses craft enzymes, and Elder Caps grow skill points, with each building costing a little more than the last
Progression: quests that pay skill points, a 10-skill tree, and a rebirth loop: save 50K sugar and 400 enzymes to awaken the Old Tree and earn Seeds for permanent upgrades
Player-friendly controls: a guided tutorial, pause and 1×/2×/3× speed, keyboard shortcuts for the whole shop, and switchable music tracks

Undergrowth's start screen explaining how it works: Root Tips, Saplings, Hypha Knots, Spore Presses, Weavers and Elder Caps, the Old Tree goal and the controls, with Play with tutorial and Play buttons — The start screen explains every building and the controls, with an option to play with the tutorial.