You are totally right, Bezzy! Based on that, here's my second attempt:
Level elements:GB is, obviously, Guy Balding (the starting point).
Vine is a vine that behaves like a ladder. It does not swing.
The floating yellow platforms are branches from huge trees.
Quicksand is... quicksand... or perhaps mud. If the player stands on it, he sinks to death (that sounds hellish, doesn't it?).
Dead tree is a weird, contorted tree trunk in the quicksand. It behaves like a platform,
and so do the other
trees (except these may have some leaves and something and stuff).
The player does not die if he falls on the
water, not matter if he was more than four tiles above it.
The
vine net is like a door. It has to be cut by the player using the
Knife, which is like a key.
The
weird leafless branch is a weird leafless branch.

It also behaves as a platform.
Goodies are three treasures/game discs/panties/whatever.
Enemies:The
snakes move back and forth to the limits of their platform, and never beyond. The "badger" one (...no, it's a regular snake) (or perhaps it could actually be a badger. That'd be funny

) moves between the two trees, and can climb that one tile high. The snakes can be stunned and rendered harmless for two seconds if GB steps on their heads. When they are stunned, collisions between them and GB are ignored.
The
spiders move swiftly in their webs - and never anywhere else -, chasing Balding as they can. The spiders cannot be defeated.
The level:The level is very simple. Guy Balding moves between branches in order to collect the knife, cut the vine net and leave through the bottom-right corner (perhaps an exit door or something should be added there to make it obvious that there is not exit above the vine net).
To reach the goodies, he has to climb the rightmost vine and then execute two jumps over three-pixels wide gaps. He then walks on the big platform, beyond the screen limits (like in the path to the Super Mario Bros.' warp zones, in the dungeon levels).
The biggest challenges are to confuse and dodge the spiders, which move very quickly, and to make the jumps.
In the background, huge trees should be shown along with the forest, perhaps shadowed by some kind of fog (so the player know which branches are platforms and which are not).
Extra pictures:Here is a version without the web and
here is a version without the text, perhaps for easier visibility.
Edit.: Typos.