The protagonist kills another character by repeatedly smashing them with a rock. The scene is intentionally blurry so nothing is seen but it can be presumed that the person's head gets squashed. Again though the scene is blurry so nothing is seen.
Every scene in the bunker is intentionally claustrophobic and visually disruptive. There are also cameras that rotate 360 degrees that could inspire vertigo.
The blood and gore is consistent with the wounds inflicted. Nothing is over the top or exaggerated. Also the violence is very economical. Nothing is without a purpose.