Microcosm is a single screen platformer where you control the Maintenance Engineer, on the crippled interstellar freightliner Nimbus, as you attempt to save the priceless cargo Terran Plant over various levels. You must walk or fly with your jet-pack around the screen and pick up seeds, one at a time from the top of the screen and feed it to the various stalks by walking over them. Once all the stalks are fully grown then you move to the next level to grow more stalks. Aphids move around the screen and these can be shot with your laser or avoided and if you touch one then you lose one of three lives. Acid drops fall down the screen and must be avoided and on later levers there are spiders and bugs that cannot be shot just avoided and if touched lose a life.