Training Room

The Training Room is used for players, mainly beginners, to practise against all enemies and bosses to improve their skill.

The Training Room can be entered after obtaining a key from the corpse of the Tutorial Knight after she has died.

Access
The door leading to the Training Room is located at the starting area inside the Prisoners' Quarters, next to the entrance to the Tailor's room and the Doctor. The door is locked and needs to be permanently unlocked via a key that can be found on the Tutorial Knight's corpse, which in turn is only accessible from their fourth total run and beyond.
 * Players who have already looted her corpse before update 2.5 will have the training room unlocked retroactively.

Entrance hall
The entrance hall is decorated with various trophies like weapons and slain monsters, none of which can currently be encountered in the game itself. There, the skeletal Tutorial Knight will explain some mechanics about the Training Room.

Further along there is a set of 3 recycling tubes filled with gear, with each tube always containing items that are always red, violet, or green respectively for each stat. The items are random, activating the lever will drop down a few items while the tube refills itself. Previous items will eventually disappear after more items are dropped down. Guillain, wearing a unique getup, can also be found for mutation selection, and with no additional cost to the player when resetting selected mutations.

Beyond there is a big door that leads to the Combat Room for training against normal enemies. Further to the back there are doors leading to boss rooms to practice against them as well.

Combat Room
Inside the Combat Room is the Ghost, who will explain the mechanics of the room. There are be various rooms, most accessed by teleporters, with enemy statues similar to those in the Slumbering Sanctuary. All enemies inside a room can be awakened by activating a lever. The enemies can also be changed to any enemy that has previously been encountered, excluding mini-bosses such as Wardens or Giant Ticks. There is also the option to choose biome presets, which changes the enemies to those of any biome which one has explored previously.

When enemies are killed, they will respawn as statues to be fought again. If the player dies, they will be sent back to the entrance hall.

Boss rooms
At the end of the Training Room there can be found doors leading to each of the bosses. The doors are arranged according to tiers, tier 1 bosses on the first floor, tier 2 bosses on the second, and the Hand of the King at the top, with a 5 Boss Stem Cell door behind a hidden hole to the right which can be rolled through. All doors are closed before the bosses have been encountered at least once. This allows for players to practice a boss without having to spend the time getting to it every time.

When entering a boss door, the player will arrive at the boss level as usual, with the Tutorial Knight nearby to motivate the player. Dying will return the player to the boss selection area without losing any of their equipped items or mutations.