Each act map is generated in full when the act starts. The rules below decide how many rooms of each type it has and where they can go.
Map shape
| StS1 | StS2 | |
|---|---|---|
| Width | 7 columns | 7 columns |
| Height | 15 rows | Depends on the act: see acts and bosses |
| Paths drawn | 6 | 7 |
| First row | All fights | All fights |
| Middle | One full row of treasure rooms (row 9) | One full row of treasure rooms |
| Last row | All rest sites | All rest sites |
How many rooms of each type
StS1 sets room counts as a share of the map's open rooms, the same in every act:
| Room | Share |
|---|---|
| ? room | 22% |
| Rest site | 12% |
| Elite | 8%, ×1.6 from Ascension 1 |
| Merchant | 5% |
| Treasure | 0% (treasure comes from the fixed row and from ? rooms) |
| Fight | Everything else |
StS2 uses fixed counts instead:
| Room | Count |
|---|---|
| Elite | 5, or 8 from Ascension 1 |
| Merchant | 3 |
| ? room | Usually 12 (10 to 14) in act 1, one fewer in acts 2 and 3 |
| Rest site | Set per act: see acts and bosses |
| Fight | Everything else |
Where rooms can appear
These rules are the same in both games:
- Rest sites and elites never appear in the first 5 rows.
- Rest sites never appear in the rows just below the final rest-site row.
- Rest sites, elites, Merchants and treasure rooms never appear twice in a row along a path.
- Two rooms that branch from the same room are never both rest sites, fights, ? rooms, elites or Merchants.
What a ? room becomes
| Result | StS1 base | StS2 base |
|---|---|---|
| Fight | 10% | 10% |
| Merchant | 3% | 3% |
| Treasure | 2% | 2% |
| Event | the rest (85%) | the rest (85%) |
After each ? room, the result you got resets to its base chance and every other result grows by its base chance. For example, three ? rooms in a row without a fight raise the fight chance to 40%. The chances reset at the start of each act.
More StS1 rules:
- A ? room right after a Merchant cannot be a Merchant.
- Tiny Chest makes every 4th ? room a treasure room.
- Juzu Bracelet turns ? room fights into events. StS2 has Juzu Bracelet too.
- A ? room can only be an elite with the Deadly Events custom modifier, and never before floor 6.
For which event a ? room picks, see event requirements and act lists.
StS1 elites
Each act's three elites are equally likely:
| Act | Elites |
|---|---|
| Exordium | Gremlin Nob, Lagavulin, 3 Sentries |
| The City | Gremlin Leader, Slavers, Book of Stabbing |
| The Beyond | Giant Head, Nemesis, Reptomancer |
When you can still get the Emerald Key, one elite on the map is marked and gets one random buff: Strength equal to the act number plus 1, 25% more max HP, Metallicize equal to twice the act number plus 2, or Regenerate equal to twice the act number plus 1.
StS1 act 4
The Ending has no generated map: a rest site, a Merchant, the Spire Shield and Spire Spear elite fight, and the Corrupt Heart, in a single column.