Siege!

Siege is a simple arcade game where the player is defending a medieval
castle. You stand at the top of the castle wall and have to throw stones at
the attackers who are climbing up the wall. Often you will be able to take
down multiple enemies as one falling man catches another. As time goes by the
enemies will move faster and faster. When the enemy reaches the top of the
wall the game is over. The more attackers you knock off the higher score
you’ll get.

Siege!