Criticism of Soma focused on the implementation and design of its enemies. While Cooke generally enjoyed the monster encounters and their "unique and frightening" designs, she felt disappointed that there were only a few different types, most of which only made one appearance in the game.
Hurley wrote that the monsters lacked "threat" and "never really deliver ... they’re little more than dumb ambulatory obstacles", being overcome by the player "looping around behind them, or slipping past while they obediently investigate thrown objects." Alex Avard of GamesRadar praised the game's "Safe Mode" update from 2017 that decreased the threat of the monsters, having felt they were originally "unwelcome interruptions to an otherwise enthralling mystery", but instead in Safe Mode gave the "high minded story the space it always needed to breath".