In Size Matters you take on the role of a scientist who has unintentionally ingested a chemical which causes him to shrink every second!
As you shrink, getting around the laboratory gets trickier, with the game essentially turning into a platformer as you figure out ways to climb up onto where the equipment and ingredients are located!
Using the equipment, you need to manage to make an antidote in a limited time, before you shrink completely! Go through the formulas you find and follow them accurately!
But beware, your time is very precious - you need to process ingredients using lab equipment all while searching for missing components or rearranging the lab so you're able to reach stuff when you're smaller!