action game that involves popping balloons with a harpoon

 Pang Zero is a clone and enhancement of Super Pang, a fast-paced action
 game that involves popping balloons with a harpoon.
 .
 The intention is to create a fun, open-source game that many (currently
 up to 6) people can play together. You can play Pang Zero alone, but it's
 a lot more fun to play with your friends.