Contra was released in 1987 for arcade platform by Konami. It was ported to NES in 1988, and is one of the best NES game in term of graphics and gameplay.
The game sets in 2633 where a meteor fall on an island called Galuga. The meteor comes with alien army that immediately set up their base in the island. Their plan is to invade the Earth as soon as their base is established.
We take control of an armed commando named Bill Rizer, or his partner Lance Bean, as they are sent to infiltrate the island to thwart the alien army plot to invade the Earth.
The gameplay of Contra is pretty simple. We need to kill all enemies that we see, avoid being killed by enemies, go through all 8 levels and kill the final boss.
We start off with simple machine gun, and can collect a few types of upgrades during the game. My favorite upgrade is 'S', which give us 5-spread shot gun that can hit a wide range of enemies.
You can download the Japanese NES version of Contra here.