after taking dark exploration to a higher level of difficulty by avoiding lighting, i learnt the difference between forest and jungle. jungles exist in our forest. it's the worse and most tiring terrain to cross. you can literally be stuck in a jungle by ground, waist and head level vines that cannot be broken with your hands. there are also sections with very soft ground. to compound the difficulty, you might get bitten by ants and mosquitos or be pierced by sharp thorns
the other thing i found are bioluminescent mushrooms. the size ranges from 2mm to 10cm. you can spot millimeter sized mushrooms while walking in a forest without using lights, whereas it's 100% impossible to find them if you need to use lights to shine your way through the forest. forget about searching for them in the day. impossible!
another thing you will see are eyes in the dark. moving eyes. it's unnerving for the uninitiated. just imagine you are alone, far from civilization, in a dark forest and you saw eyes looking at you from dark sections of the jungle. note i use jungle here, not forest. because these eyes prefer lurking in dense vegetation, and not forested or open air sections. you won't see eyes in the day. only at night!