Structures spawn beside the track about every 7 km, usually between a little wall and a large wall. Most often that is a dungeon, a Mineshaft, or a Vampire Mansion. Harder structures only appear from a set layer down. Ratings run from 1 to 5.
The first dungeon is guaranteed in the Grass Layer. One note puts it at 1,000 m. The structures note says 3 km. Clear it either way. It is the first scrap and the first chests.
| Structure | From | Rating | Enemies | Notable loot |
|---|---|---|---|---|
| Dungeon, level 1 | Grass | 1 | Goblin, Goblin Brute | Scrap, chests |
| Spider Tunnel | Dirt | 1 | Spider | Chests |
| Mineshaft | Dirt | 2 | Watcher | Ores and gems |
| Dungeon, level 2 | Stone | 2 | Goblin, Goblin Brute, Spider, Goblin Lord | Scrap, chests, Goblin Lord Crown |
| Dungeon, level 3 | Stone | 3 | Goblin, Goblin Brute, Spider, Mole Man | Scrap, chests |
| Vampire Mansion | Clay | 4 | Vampire | Vampire Key, chests |
| Spider Dungeon | Crystal | 4 | Spider, Venom Spider, Red Widow | Chests. Crown name conflicts: Red Widow Crown on the structures page, Fire Widow Crown on the Fire Widow page. |
| Goblin's Arena | Crystal | 5 | Goblin, Goblin Brute, Goblin Knight, Goblin Champion | Champion helmet, chest, legs, and hammer |
Spider Dungeon wave counts are listed as 10, 20, and 20. The lair pays five high-tier chests.
How to clear them
Loot sits in the corridors, not only in the boss room. The boss room is waves, then a boss, then three chests. A level 1 boss wave is a Goblin Brute. A level 2 last wave is the Goblin Lord at 3,000 HP, with a 1% crown drop. The Arena champion is 10,000 HP. The Fire Widow is also listed at 10,000 HP.
Mineshafts are the ore detour. A later mineshaft edit says Heartgem can appear above 1,000,000 m, and that the tunnel end has an Emerald or Ruby plus minecart items. Watchers are the listed threat. A 10 October 2026 Prospector note adds a level 4 perk of +100% Mineshaft spawn chance, with a requirement of 10,000,000 m total depth. That perk is newer than the four-level class tables.
When to skip
Skip only when the drill is out of fuel or the next boss wall is already in contact. A skipped Grass or Dirt dungeon is lost scrap you needed for Common cards. From Crystal down, the Arena and Spider Dungeon are optional if the party is low on medkits, because both bosses are 10,000 HP fights on top of a 10,000 HP or larger wall.
Churches are separate from this table. They are the save points past 100 km, covered in the Infinite Mode guide.