Things I think you should consider not having in the Forest Biome:
- Pink Spiders
- Hole Jumping Squids
- More than one purple flying follower at a time
I think it's okay for the Jungle to be a bit difficulty spike. New players are still trying to learn how to roll back and forth. Having them contest with a large number of enemies, some of them chasing and having multiple hit points makes it quite a bit harder to learn and experiment.
On that note, I kinda wish you started the forest with one random room. That means players will get a chance to explore a variety of mechanics (assuming they hit the 2nd random room at the half-way point) in the relatively safe space that is the Forest.