Q: How do I destroy my friend?

i just started playing and I'm pretty garbage, please help :)

Hey, thanks for playing the game! Here are a few tips:
- Disasters do predictable amount of damage. If before the first Disaster is drawn your castle has 2X, 2 Moon and 2 Square protections, then you're guaranteed to not take damage. With the second Disaster all you need is 4 X, 4 Moon and 4 Squares and so on. If you prioritise getting these protections you can then build whatever you want afterwards, giving you lots of possibilities.
- Grab the Bunker or Safe Room whenever you can. They're incredibly powerful defensive cards that will do wonders for beginners.

 
Bunker
Safe Room
 

- Grab Vaults whenever you can. Simply playing to make sure you aren't taking Disaster damage and grabbing Vaults is a very powerful and viable strategy.
- Try to build your castle with a strategy in mind. Certain cards in Disastles, like Commanders Chambers, Gravity Generator or the Market will win you the game if you manage to enable them and use their effects properly. Don't pick too many of these cards though. They require your castle to be build around them and having too many will weaken your overall strategy.
- Keep links open. It isn't always the best strategy to use link effects right away but instead it's usually better to have at least one easy to activate link available at all times to undo an attack your opponents did on your castle or to prevent them from growing too powerful.

Commanders Chamber
Gravity Generator
Market

I hope this helps and I hope you enjoy the game!

Homeowners Association

Homeowners Association allows you to “rearrange” surrounding rooms.

Rearranging allows you to pick up all cards surrounding Homeowners Association and place them anew. It’s very important to remember that placement rules must still be respected. This can be used to reactivated links although not the one from Homeowners Association.

 
Homeowners Association
 

Entropic Vault and Generator

When an Entropic Vault or Cold Vault would be powered by an Energy Core they override the energy core effect. This doesn’t mean the vault is active but instead simply that it can’t be activated by only the Energy Core or Generator. Negative effects override positive effects. If an Energy Core would be active and is connected to a Cold or Entropic Vault that is also properly activated through connections the Cold or Entropic Vault overrides the Energy Core and deactives it.

Energy Core
Generator
Entropic Vault
Cold Vault

Can a Link be activated multiple times?

Yes and no. Once a Link has been connected it instantly activates. If the card is then left alone and nothing changes, the Link can't be activated again. However, if you manipulate the cards in question in some sort of way, for example by swapping the room that activates the with another room that can also activate the link, you may use that link effect again.