Editing a game

The editor is guest-friendly: paint a map first, sign up when you want to keep it.

Map cells

• Spawn — monsters enter here (need at least one).
• Exit — monsters leave here (need at least one for most modes).
• Castle — Defend the Castle objective. Paint it on any cell.
• Path — used by Monster March as the painted lane.
• Tower pad — preferred build sites for towers.
• Ground — open terrain (buildable if “allow ground build” is on).
• Wall — blocked cell for mazes (Monster Rush).

Tip: click a cell with the same palette tool selected to clear it back to ground.

Game types

• Monster March (monster_march)
• Monster Rush (monster_rush)
• Defend the Castle (defend_the_castle)

Monster March follows painted paths. Monster Rush pathfinds; when blocked, monsters attack the nearest wall/tower on the dig route (Chaos mode keeps smashing the shortest line). Defend the Castle sends monsters toward painted castle cells, which can sit anywhere on the map.

Towers, monsters, waves

• Towers — cost, health, damage, range, cooldown, weapons, elements, and flat upgrades.
• Monsters — HP, speed, score reward.
• Wave types — which rounds run, monster groups, and scaling by appearance or round.

Guests have lower type caps; registered accounts get higher caps. Limits show in the editor header.

Publishing

• Public — shareable play link + gallery eligibility.
• Allow download — others can download the OpenTD JSON export.
• Use Dashboard to manage games, import JSON, and copy play links.