One aspect of Hevn that is very important for immersion is the audio and sound effects - specifically the "muffling" of sounds. By "muffling" I mean adding a low pass filter to an audio or sound. If you're unfamiliar with what a low pass filter does, imagine listening to music playing from a separate closed-off room from the one you're currently in. The lower frequencies (i.e. bass) can be heard through the walls while the higher frequencies are attenuated, or not heard as clearly. In this post, we'll discuss how this is currently handled in the game.
Hevn is being developed to be an immersive first person game. A huge part of this immersion is the sound that the player makes in that world, whether it be footsteps, breathing, picking up a box, etc.
Early on I knew the the sounds the player would make would vary according to the environment and actions. If the player walks on concrete it should sound different than a metallic floor. If the player breathes in a thin atmosphere, the breathing pattern should be different than in a controlled indoor environment. If the player picks up a rock and inspects it, it should sound different than if they were to pick up a spoon. If the player walks in tall grass, it should sound like it. Another design goal was to minimize the repetition of the same sound.
More game design details at IndieDB