Granny Pills - Defend Cactuses

In a post-apocalyptic 2075, oxygen is scarce and cacti are the Earth's last hope. Join a brave granny in her epic mission to protect these vital plants from invading aliens! Armed with a stockpile of color-coded pills and a trusty shotgun, you must blast away extraterrestrial threats to save the planet. Can you survive the onslaught and keep the last of the greenery alive?