MArcomage

When the opponent raises their wall and tower on the same turn, and you then play a siege card, it should lower them both, right? I just played a game where my opponent played Lookout towers over a green card, and got +3 wall +12 tower. I played Clay Golem after and got a bonus to -wall, but no tower reduction.

Edit: Replay

It's ADDITIONAL damage. So you have to reduce tower to trigger Siege.

NG_Beholder is right. You have to do damage to Tower/Wall to trigger the siege keyword. The idea behind is that newly constructed building suffer more damage if hit.