I completed the game in hard first to learn the basic, the second run was very hard iron mutant and i did it in first try without loosing a crew, the second half was way too easy. The enemies could have more hp, better ai or just simply more of them. In the 2/3 of the game im go in almost without stealth kill, just choose a good spot and you good, not even been shot…
Once you know what you’re doing the game does get easier as most things do. Full encounters are too short. You can basically two shot any normal enemies and use mutations for the rest. Hog Rush for Sect Brothers and Chiefs, Twitch Shot for Tanks. Rarely do you have to deal with more then 2-3 enemies at one time. Mutation cooldowns are easy to manage even if you’re doing a speedrun. All Mimirs and Bots are a joke due to reliable stunlocks. Even with all of that though the game is still extremely fun and satisfying. Especially if you challenge yourself with restrictions like no damage, low level runs, or only using the lowest tier weapons. I would suggest a difficulty that increases the amount of enemies you have to face at once. Tanks and Bots x2, Hunters and Pyros x3, Marauders and Butchers x4. Reduce duration of all EMP effects by 1 and chance to proc by half. Increase cooldowns by 2 kills each to compensate for the increase in enemies. Sounds like a great time right?
Edit: Also, the Tanks have Hog Rush so give the other Ghouls some skills. Hunters get Knee Shot + Alpinist, Pyros get Pyromania + Contortionist, Marauders get Run n Gun + Twitch Shot, and Butchers get Dodge Dash and Skull Splitter.