I tried to ask around in game but people either weren’t answering or didn’t know
Why is there a 20 min cd after donating to alliance? I can still donate, so what is the cd for?
What happens when someone attacks your hill? What do they take? Is there any way to defend other than pop a shield up?
What does ‘war day’ mean? I saw people saying this in the chat
Hey @H.Ichigo
Welcome to the Ants Forum space. ^^
I hope I can shed some light into your questions. 
There is a cooldown period, so you can’t push alliance evolution unlimited. Each player can use their 20x donations and then every 20 minutes, you get 1 additional donation point. That means you get around max. 90 donation points, if you don’t use the diamond option as well…
If other players attack your hill, they first meet your stationed troops in the building, depending on who is stronger, those troops get hurt or even killed and land in the healing pools. You can raise your defense, by leveling up the pink mushroom building, troop evolution, troop level and amount plus your insect level and special ants.
If they successfully defeated your troops, they will walk away with a certain amount of your ressources.
Certain servers have “War days” or “Purge days”. Those are basically 24 hrs or more, where you get attacked nonstop if you don’t have a shield raised up. It all depending on the alliances of each server and how well they get along with each other.
If my troops are all out gathering resources, does that mean my hill is undefended?
Yes. Since you only have 4 troops that can do anything at a time. So they’re either in hill or outside. Same if you attack something. Those troops will also not defend.
I see, thank you so much!