Completed my playthrough!
Very good mod! Later in the campaign I had rocketlauncher troops, toughened officers, dogs, drones, helicopters, tanks and power-armored bosses attacking me. The entire roster works really well and is definitely harder than regular doom enemies, but still fair and managable generally.
Especially units that shoot rockets can quickly and easily reduce my health with surprise attacks - I think giving them a slightly longer delay and warning before they shoot their rocket would be welcome.
Ammo drops are massive, I never ran out of ammo for my chaingun/shotgun slot weapons. Its a bit 50/50 situation - on one hand I don't need to rely on map placed ammo pickups which makes scarcity-based challenge gameplay not possible, but on the other hand the abundant ammo is excellent at balancing out the harder-than-vanilla difficulty of this monster replacer mod.
Some voicelines say some really funny things, I love it.

Because I understand russian language, this mod is far more entertaining due to the various things the enemies/hostages will say and how they say them.
Third party addons like Nash gore, Critical Hits by mikk- and similar greatly enhance the fun too!
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On a sidenote, the update for the mod didn't appear in my moddb update feed, so I fear many people might not even know it got updated there.
When uploading a file, theres a section at the bottom to add Links that will cause moddb to send updates to people who are following a game, a mod, a group or engine. If you can make that section look like this (see below) it would add more visibility and discoverability to this awesome mod:

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As a suggestion, can you add some sort of easily visible bright colored green icon hovering above the heads of Hostage characters?
Normally because I use Target Spy to see enemy names, I can identify hostages directly somewhat - but without that addon UI mod I'd have to let a potentially dangerous unknown human character move around freely for a bit, without shooting at them, to give time to identify if they're friend or enemy. Even then with that mod I still make mistakes and shoot them down, thinking they're an enemy in the critical second as I turn a corner and suddenly see them.
Having an icon above their heads (like a green double arrow pointing down or a green H or a green human icon) would greatly help saving hostages among enemy groups. I've already massacred a lot them by accident in numerous fight-or-flight moments, feeling regret and anger I fucked up.