The Bitter Forest is one of the newest rooms in Panfu. It was added in September 2013. Like Bitterland, it is disliked by many players, and alot of pandas don't even know it exists, as it was part of a weekly quest and never mentioned after the quest ended.
The rooms uses the same colors as Bitterland. It looks like it was pained with watercolors. There's not much to do here, except for playing the unfinished minigame Panfu Defence.