Commander Keen - Episode One: Marooned on Mars

Billy Blaze is an eight-year-old genius who built his own spacecraft at home, under the watchful eye of an unsuspecting family. When the boy uses a vehicle to get to Mars, he accidentally discovers that foreign Vorticon representatives are stationed on the Red Planet, preparing to invade the Earth. The aliens decide to imprison an inconvenient visitor and steal four key parts from his rocket. Their recovery falls on the player's shoulders, so it's up to him whether Billy will return home and warn humanity against the attack of hostile beings.

Marooned on Mars is the first edition of the Commander Keen series, which was developed by id Software in 1990. The action of the game is divided into two parts. In the first one we observe Billy from a bird's eye view and decide which Martian city he should go to. After choosing a location, we move on to the second part, which is already a classic platformer. The hero can move on the platforms visible on the board and kill numerous enemies with a pistol. The aim of the game is to recover the previously mentioned parts, which may or may not be in the visited city, and also to find an exit. If Commander Keen dies, the action moves back to the surface of Mars. The fun can continue until you lose all "live".