Here’s how to reach the arboretum and the swamp
It never hurts to have a map handy for Dead Cells, especially as new areas join the flow-chart-like world. The Bad Seed includes two early-game biomes, as well as a third area that’s home to a new boss.
These DLC zones are by no means hidden – seasoned players will find them without trying – but if you’ve taken an extended break from Dead Cells and you need a primer (or you’re a relatively new player who hasn’t unlocked the basic ability runes yet), this updated map is worth consulting on your next run.
In short, The Bad Seed areas are green on the map. You’ll want to have the Vine Rune (obtained in the Promenade of the Condemned) and the Teleportation Rune (unlocked in the Toxic Sewers).
Starting from the Prisoners’ Quarters, you can quickly reach the Dilapidated Arboretum (the mushroom zone), which then hooks into Morass of the Banished (the swamp). From there, you’ll take on Mama Tick in The Nest. And… that’s it! Those are the basics. Again, The Bad Seed doesn’t try to obscure anything.
After facing the boss, you’ll be able to venture into the Graveyard or Stilt Village, and carry on normally.
Explorer’s Guide Progression Map by Ray G. Quit and ConnorToby1 [Dead Cells Wiki]