Castle clout is a skill game where you've to take out the king and his flag. You can do this by launching the trebuchets' ammunition at the right time. This will cause maximum damage to the castle.
You'll get points if you make a headshot, or destory the flag, ... The more points you have, the better weapons you can use. So always try to get as many points as possible!
If you've finished all the levels, you can even build your own level!