The Wormatrix. Kind of like worms world party and soldat. Make sure before you start playing to make your own weapons or to go to the "Weapons" button, hit L (for load), and type WWP (make sure to unzip all the files). This loads the worms world party weapon set.

You can make your own weapon sets with tons and tons of possibilities - completely customizable. Also you can make your own levels just by drawing gifs. It comes with several already made level images though.

Author's note:
The game's a little difficult to play, but can be fun at times against human opponents with crazy customized weapons.

Editor's note:
Looks interesting, you can make your own levels and weapons. The computer player is tough.