That’s it, just let this thread make challenges. Not entire new gamemodes, things kept in a separate menu that entirely change how the game’s played.
#Let us make challenges
wild quail
river zealot
The sentence is too vague, are there any examples?
jolly stirrup
That’s it, just let this thread make challenges. Not entire new gamemodes, thing...
no engines
no troops / only guns
no guns / only troops
only first level buildings
only first type generator(forgot how it called)
no artifacts
wild quail
I think the spirit of some of those can be kept.
normal timber
No jellyfish (ultra hard mode)
peak goblet
U mean horizontal?
1x2 then.
peak goblet
No "Beacon" modifier.
No turrets.
Only turrets.
Only Black generators after [number] wave.
random hawk
I accidentally did "No deleted constructions or turrets" because I didn't know it was possible 
but that would be a fun game mode, if you get a buff. You have to plan for the long term/not build cheap stuff
peak goblet
No T1 or T2 defense units. Only T3 defense units.
peak goblet
No turrets -> No hull ruptured.
random hawk
That one might not be possible but:
No interaction with markets, shipyards, always pick the random event option that gives no reward (if possible). Basically only use shop after wave
peak goblet
Do not buy any module kits in after-wave-shops if they are sold in workshops. I mean to buy Fuel Gen-rs, Microchip Gen-rs, Human Storages, Jellyfish Gen-rs, Human Converters and Engines only in workshops.
normal timber
After each wave, randomly get a weapon, 2 unique modules and every 4th round you get a relic
peak goblet
Do not build a new module until the previous module of the same type has been updated.
wild quail
Maybe just a Highlander mode for one. No repeat turrets or modules, except for the human storage
normal timber
Isn’t that just how you play the game though?
wild quail
Isn’t that just how you play the game though?
No.
normal timber
Oh oops