It’s a bit of a diversion from the chainsaw topic but:
Why hasn’t the cataclysm cause more weird weather effects? Acid rain doesn’t even happen anymore since its current implementation would realistically just kill everything.
A fog that starts going from one side of the map to the other, and really weird stuff happens in it, like humans with their skin turned inside out, balls of screaming flesh that float about, dogs with human faces… dammit now I want this in the game…
Cursed booze rain or whatever it was from dwarf fortress.
Orbs of destruction. Float through everything, travel in wandering paths that have no regard for anything else. Will demolish anything they touch into nothingness, and can travel through any z level. Sometimes even wandering through Z levels.
Speaking of monsters, why do only human zombies evolve? animal zombies should too, here is some proposals:
Antlered horror evolution:
Zombear evolution:
Zombie titans.
Hordes sometimes condense into a single being with unlimited height and size. Comes in 2 types
Composite: each individual zombie remains intact, and they just lego themselves into a larger zombie
Biomass: the zombies are only used for their parts and mass. Same as any other living creature the titan eats. Basically a super blob with zombie parts for armor and utility/abilities. including spitters, screamers, necromancers, and shockers. Only zombies absorbed or evolved inside them count towards this though. Or not, whichever.
I figured biomass would be similar to the jabberwok.
BTW elder jabberwok a being that has killed and absorbed so many bodies that is now a multistoried mass of screaming body parts and flesh.
similar. We need more giant, near indestructible enemies. Because terrible ideas.
Read my edit.
The Aliens from the AVP series. Head huggers included. Also every headhugger from every other game and movie ever.
On the weather front…
Fungal “sand” storms.
Blood rain.
Eclipses.
Meteor showers.
Floods.
Also Earthquakes and fault lines
volcanos
Tornados/huricanes
Blood moons
fish rain
hail storms …with like REALLY big hail… your tanks is going to wonder whos firing on it.
shrapnel storms -dust devils on steroids
HUGE sandstorms
Fire tornados 
And the most dangerous weather… MAN!
ACID HAIL with a chance of portals and live military ordinance.
hurricanes and other weather often pick up lose live military ordinance and throw them around among other things.
Crashing drone bombers.
I was thinking about what else to suggest and remembered lava already exists and my !!Science!!mind got activated.
[ul][li]lava rain[/li]
[li]sudden random geysers[/li]
[li]squirt gun filled with lava[/li]
[li]lava elementals, Fire Zeds and hell daemons[/li][/ul]
Oh god the ideas just don’t stop coming and every one of them would mean nothing other than fiery doom…
With all these fantastic ideas, life for the player will become much too difficult, so we should make improvements to help the player like bettering the pet system, currently dogs and cats are kinda useless in a fight, so they should be treated as NPCs and have their own equipment and skills, which would naturally improve and of course once we are able to teach martial arts to NPCs our pets should be no different:
My cat is already plotting to kill me. The only reason why cats haven’t already killed us all is they can’t do things like use bladed weaponry.
Thats why we keep dogs. Please note: it is recommended that you only train your intelligent dogs to be samurai, as the less clever will be inclined to rub up against you while wielding a sword like they would their favorite stick.
Just a friendly piece of advise.