Sample mod - Living Trail

A board on the stock pit that grows with its trail. The run opens on a short trail out of the cave, and the insects come out of its far end. After every wave the trail walks on three cells, winding into the pit, and the insects come out of the new end. Only the ground beside the trail is open: the rest of the pit lies under rock, and the rock sinks into the floor as the trail reaches it. You build only on open ground, never on the trail, and the trail winds around your towers.

It is a Workshop sample (steam_build/workshop_samples.txt): the game's package leaves it out, and it reaches players once published from Options → Mods. Enable it there and restart. Like any gameplay mod it plays on its own mod profile, so your vanilla save is never touched.

How it works

It is data only (balance.json), on the game's route_growth rule in its frontier mode (see the modding guide, "A living route"):

• start_cells 6: the opening trail, straight out of the cave.
• cells_per_wave 3, max_cells 130, from the first wave. On the stock pit the trail fills the floor at about 50 to 100 cells and then stops growing.
• margin 1: the open ground is the trail and the cells beside it, diagonals included.
• The open-route pressure is off (enemies.open_route_pressure.max_mult 1): it multiplies the insects' health when a maze is short, which punishes a player who leaves the way open. Nobody here can shorten the way.
• No scattered rubble (map_data.json and difficulty.levels): it would only wall the trail in.
• Waves keep vanilla's health. The earlier meandering trail needed 20% more at Normal; the short opening trail is harder by itself. A first run (level 1) lasts to about wave 10-12 at Normal, against vanilla's 3-10, and to wave 3 at Nightmare, as in vanilla (docs/balance/2026-10-10-mod-samples/README.md).
• Cards, towers, the factory and everything else are the game's own.

bots.json lets PvP bots play it: each bot grows its own trail around its own towers and builds only on its own open ground.

Change the numbers in balance.json to try another pace: more cells_per_wave makes a long trail sooner, a larger margin opens more ground for towers, and "mode": "meander" keeps the whole pit open with a trail that bends between the nest and the cave instead.