Penguin Adventure (夢大陸アドベンチャー, Yume Tairiku adobenchā?, lit. "Dream Continent Adventure") is an action-adventure platform video game released by Konami in 1986. It is a sequel to Antarctic Adventure and has the distinction of being the first game that game designer Hideo Kojima worked on; he was an assistant designer. It has been acclaimed as one of the best MSX action games for its gameplay, depth, variety and rich pseudo-3D sprite-based graphics. The story follows Penta, a penguin who has to bring home a golden apple in order to cure Penguette (Penko Hime in the Japanese version), the Penguin Princess.
This title significantly expanded upon the gameplay of Antarctic Adventure by most notably adding a greater variety of stages and enemies and RPG elements: boss fights, purchasable items, and several mini-games. Items can be purchased through three different fisherman, in exchange for fish, that give Pentarou new abilities. One of the items that can be bought is a gun, which reflects the charactization Pentarou is given in his appearances in the Parodius series. Level design and variety has increased from Antarctic Adventure; there are forest levels, ice levels, water-based levels, caves, and even an outer-space bonus level. There are several shortcuts, usually hidden underneath holes (which are typically harmful hazards) in the game, that allow the player to go on almost completely different paths. The game also featured multiple endings, with the hidden good ending available when the player pauses the game a certain number of times.
Source: Wikipedia, "Penguin Adventure", available under the CC-BY-SA License.