Jupiter Express is a simple action game that is played on a single screen. The player controls a space ship which is travelling between Mars and Jupiter and the aim of the game is to guide the ship through an asteroid belt without crashing. The ship starts out at the left and moves slowly forward while the asteroids move from the opposite direction. The player's control is limited to moving the ship up and down and by reaching the right edge of the screen the game is completed. Any contact with an asteroid leads to a crash and the game being lost. Before starting out it's possible to choose a difficulty from zero to nine.