Okay so I played through this on No Mercy on normal. I started on Expert but Expert offline, at least to me, is nearly impossible without a LOT of patience, a decent starting gun and good RNG. On Expert, Boomers can also spawn directly in your path and instantly incap you ending your run.

Even on normal difficulty, I didn’t find this mutation particularly fun. The nerfed guns feel underpowered, and the constant special infected spawns are pretty tedious to handle, especially with only one bot as an ally. Specials often spawn seemingly out of nowhere, dealing high damage or immediately pinning you. Making it to the saferoom sometimes feels like it’s based on good RNG rather than skill.

Also, witches can end runs by themselves by blocking the way forward and they are impossible to kill. I tried to crown one and it just straight up didn't work.

The only gun that feels good to use is the Grenade Launcher, which I genuinely think was nerfed to deal zero damage since it didn't even 3 shot a smoker and entire clip didn't kill a Tank during the finale.
The other guns are all way too slow at shooting or practically don't deal any damage. The double barrel, for instance, doesn't even seem to two-shot most of the specials when you're standing directly in front of them.


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Here's my sort of tier list of the infected from weakest to strongest:

Common Infected: They might as well not exist. Any that spawn instantly de-spawn if they attack you. I think they're supposed to be shadows but on some maps they're fully modeled and just disappear upon hitting you. Essentially they just damage sponge a bullet if you happen to hit them which just makes them a nuisance at worst. I didn't play a campaign with uncommon so I don't know how they work. I imagine riot zombies would be annoying still since they can eat bullets without vanishing?

Smoker: Literally useless. They walk into viewing range and then just stand around unless you get too close. Sometimes they just seem to refuse to attack at all.

Witch (If not blocking path): The long aggro time often makes them really easy to avoid unless they're actively blocking the way.

Hunter: Pretty weak overall. They walk up to you and then scratch but since they don't seem to pounce that makes them really slow and easy to pick off. I think a hunter might've pounced on me one time but I barely remember since Hunters were not as amusing as Smokers.

Spitter: They can deal some damage and like to constantly spawn but otherwise they're mostly just the vanilla spitter. Not hard to deal with.

Boomer (Advanced(?) and Below): Boomers are unexpectedly tanky and tend to appear around corners, making them frustrating due to their timing / positioning rather than how strong they actually are as an infected.

Tank: Weird placement yes. They seem to be slightly faster than the player, they're primarily frustrating primarily due to their excessive health, which slows down the game tremendously. It took me multiple weapons worth of ammo to take down a single Tank, and finales are still two tank finales. I used the Grenade Launcher on No Mercy Rooftop to try to deal with it but it seems to do no damage because even 30 shots from that didn't kill the Tank. Aside from that the Tank isn’t really all that dangerous it just takes a lot of time to take down, which feels tedious. A gas can could've maybe solved this but I had already used them up earlier.

I didn't see a tank spawn during regular play (only witches) so I'm assuming they can't under normal conditions. A tank during regular play would've been pretty much impossible to deal with.

Charger: Chargers can pretty much *instantly* re-charge after missing a charge meaning if you don't kill it you're probably getting hit and getting incapped. Chargers can often appear directly around a corner where you're guaranteed to get hit and since they have good HP they can often just tank your bullets and charge you for free if you can't get away from them in time.

Jockey: The gun nerfs make Jockeys even more frustrating than usual. They're still pretty fast, which means if you miss you're really vulnerable especially due to the decreased clip sizes and slower firing rates. The best way to deal with the Jockey is to either get a lucky shove or hope they just don't spawn that often.

Witches blocking the only path forward: You sacrifice your bot to it, die or hope you have a lucky gascan spawn. Might be possible to get past it with adrenaline or good juking after throwing a pipe-bomb in some scenarios. It's pretty much just RNG at that point. (Good luck running from a witch when you have specials you can't see blocking your way all the time.)

Boomer (Expert): I'm putting this in its own spot because on Expert Boomers can spawn, round a corner and incap you instantly. I lost like 7 games in a row on No Mercy CH1 just because a boomer spawned directly behind a corner and walked into me. Shoving it isn't consistent and it's too damage spongey to kill. Do not play this mutation on expert in offline mode.

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It's a really cool idea but I feel like it's only really balanced for Normal and Below (at least in offline mode) and even then it still feels unfair. That's probably the point considering the inspiration, you SHOULD be struggling to survive but I definitely feel like the mutation in its current state is more luck based than skill-based. Could be a skill issue but that's just my opinion.