Nihon Bussan's Mission-X had a similar vertical scrolling shooter gameplay to Namco's Xevious, released later in 1982.
The arcade game was later ported to the Intellivision console by Mattel Electronics in 1983.
You are a fighter plane bombing ships, bridges, and tanks, occasionally you use your guns on other planes that attack you. Shoot oncoming planes and ground targets using your gun. Bomb all enemy sea and land craft, gun emplacements, bridges and transportation networks. A low flying attack gives the best hit ratio but be careful, it is dangerous.
Mission X lets you fly right and left while the action scrolls forward vertically. However, instead of letting you backup or go straight ahead on the screen, pressing up and down on the control disc causes your bomber to lose and gain altitude respectively. This way you can duck under or fly over enemy attacks. This is the key difference between Missile-X and the Xevious series.
At the end of a level, you will need to try touch down your plane to the runway for bonus points. Land on the air strip for extra points between stages.