In Doraemon, you must clear three Worlds to beat the game. Each World is like a game unto itself.
The first world is a city world which Doraemon must explore in order to collect various weapons, and ultimately locate and challenge the boss that lives in a factory next to the cemetery on the outskirts of town. Various power-ups increase Doraemon's strength, and ability to defeat enemies. Getting to the cemetery will require clever investigation, as the entrances to reach it are often hidden.
The second world is a side-scrolling shooter through a dark location broken up into three parts. It is infested with enemies who try to stop Doraemon at every turn. Side passages will appear from time to time, and can be taken in order to locate kidnapped friends who assist Doraemon and to collect power-ups. The official pathway ends in a loop, and the correct passage must be discovered to break out of the loop and reach the final boss.
The third world is an underwater adventure that shows one screen or room at a time, and Doraemon must swim from screen to screen in search of items that will help him unlock treasure chests and rescue his friends. One special bag will allow him to transport two additional items. You must figure out how to most efficiently juggle the three special items, and bring all of the children to the underwater gate so that Doraemon can rescue Shizuka Minamoto. Watch out for the thieving ghost!