Interactive elements of the environment:

Surface types

Impassable darkness

Zone that's unaccessible for both players and enemies. Map boundary.

Ground

Basic ground that player can walk on. No special attributes.

Shallow water

Area that both hides player and allows to dispose of enemies easy by drowning them.

We need something to balance that, here are some ideas:

• Water makes player invisible when they're still, but makes noise and lingering waves when player moves. Fast movement alerts enemies.
• Enemy downed in water is downed for longer, but is loud, splashing water and shouting.
• Enemies can probe water - throw rocks inside. Riples around the rock make player visible if they're near. Also if by chance they hit player, they also loose one hp.
• Dragging enemy to water makes noise.
• Enemies are more suspicious if they're near water - they can't be easily dragged into, unless they turn their back to us. this seems to be the best idea - as in I know how to do it easily, and it adds something valuable to gameplay
• Maybe the shadows work the other way - you're visible in shadows in water (cause there's no strong reflection to conceal you)

Immovable objects

Bushes

They hide player. Player becomes invisible unless enemies stumble on them. Perhaps they can be burned down or otherwise destroyed by enemies? Would be cool if enemies could probe them with their forks.

Wooden walls

Can be destroyed by throwing something heavy or an explosion. Walls of buildings in the village.

Trees, giant rocks, stone walls

Just impassable barriers.

Movable objects

Barrels, crates etc

Concealing elements, that can be moved, pushed at enemies, or used as shield against enemy projectiles or sight. Easy to destroy. Maybe can be grabbed, maybe thrown - but only in fury mode.

Weapons and other small props

Enemy weapons, like spears and forks. Also small elements of the enviro, like stones or logs (if needed). Can be grabbed and thrown. Usually destroyed on contact with enemy or ground.