I understood what you had to do, which was to shoot greenish-yellowish parasites, but it just wasn't a good game. The "parasites" which were polygons and moved randomly. It did not seem like the green ones fed off of the red ones and all the shapes followed similar routes which reset very ungainly. Some of the menu screen was not visible for whatever reason and I had trouble reading the "help" area.
Work on how the parasites move and how the parasites look. Right now I think the game you've submitted should be blammed.