For a better immersion of the player, we have established a sound management in 2D. Basically, if an item makes some noise on the player right side, you will hear the sound loudly from the right speaker and very faintly from the left speaker. Farther you are from the item, the less you hear it obviously.
Each element of the game, like the ground, boxes, branches, rocks, characters or monsters have a material type. For each material, we associate a collision sound of the materials in question. Thus, a rock hitting the player will make a rock impact sound associated with a flesh impact sound.
Nothing really complicated. To this, we add some sound effects for the player death and jumps, a few sound effects for the various items and that's all there is to it. Now we need a good sound engineer to do quality work !