Granny Pills - Defend Cactuses

2075 year. After the invasion of aliens, there was almost no life and oxygen left on Earth. The only plant that survived are cacti. The aliens want to destroy or steal all the cactuses to stop the live on Earth.
The brave Granny who grows her cactuses on the road (so that they can receive rays of light) should protect them from aliens. She discovered that the aliens are afraid of human pills, and she has a huge amount of them, as well as a shotgun loaded in case of emergency.