There you're walking, in the mountains, all alone, without knowing where you are or how you got there. Time to get back to civilization! Jump on the red buttons to open doors. The pink creatures are out to kill you: they shoot at you and you can eliminate them by jumping on top of them. Watch out not to bump into them, either! Sometimes you'll have to continue underground to take certain obstacles. Jump on the sharp buttons to continue underground. There as well all kinds of dangers are lurking: avoid them and try to eliminate them! Jump on a key button to get back to the surface.
Use the left and right arrow key or A and D to walk. Press the up arrow or W to jump. Also press the up arrow or W to open doors.