Concept 1

In concept 1 area, I want to introduct the sense of horror and danger, so I use the lighting green near the player to give a sense of unnature feel. Red, orange and yellow are use for the next area to give a sense of danger to the player.

Concept 2

In concept 2 area, player pass through the concept 1 area, and showing the sky to the player for the first time. The sky give a sense of the space to player and introduce new element to player eyes.

I'm working on concept art right now. Will be finish most of the concept art soon.
Then I will go on to making a game asset list, so that when going in to production, we can just refer to the asset list and create the game asset that we want in our level.

I will update again once I finish the concept art.