Chapters are sets of floors which contain similar enemies, themes, bosses, and difficulties. Earlier chapters are divided into two floors, while later chapters contain one floor. Each chapter has different environments which, while retaining the same feel, have slightly different themes, enemies, bosses, and difficulties. Each environment also has its own music.
Chapter 1
| File:Basement.png | File:Cellar.png | File:Burning Basement.jpg | |
| Basement | Cellar | Template:Afterbirth Burning Basement |
Chapter 2
| File:Caves.png | File:Catacombs.png | File:Flooded Caves.png | |
| The Caves | The Catacombs | Template:Afterbirth Flooded Caves |
Chapter 3
| File:Depths.png | File:Necropolis.png | File:Unnamed Depths Alt.png | |
| The Depths | Necropolis | Template:Afterbirth Unnamed Chapter 3 Alt |
Chapter 4
| File:Womb.png | File:Utero.png | |
| The Womb | Utero |
Chapter 5
| File:Cathedral.png | File:Sheol.png | |
| Cathedral | Sheol |
Chapter 6
| File:The Chest.png | File:Dark Room.png | |
| The Chest | Dark Room |
Template:EnvironmentNav Template:MasterNav