Contra (USA) ROM

Contra in my opinion, is one of the best shoot'em ups out there, and still probably is. I even despised shooters, and I was still thouroughly content with this game. The controls are intuitive, and not difficult to handle, a plus considering the stiffness of other NES games. You can also collect red letter's with wings that give you different guns(My favorite is S :P) and are also allowed to shoot in multiple directions. The visuals are also quite detailed, considering it platforms on the NES, and the quality is much like the Castlevania games of the NES.
Be warned, as you are in for one heck of a ride, bullets coming at you at every conceivable angle, traps and pits that can get in you're way, and the fact that one hit kills you, and takes away your meager 3 lives (Which can be brought to 30 if you use the Konami Code.)
Sadly, this game is a bit short, and the levels aren't as expansive as one would think. In any case, it is a truly great game, and well deserving of its popularity and appraise
 

The universe teeters on the brink of total annihilation at the hands of the vile alien warmonger, Red Falcon. Earth's only hope rests with you, a courageous member of the Special Forces elite commando squad. Your mission: Battle deep into the deadly Amazon jungle, where the Red Falcon and his galactic henchmen have transformed ancient Mayan temples into awesome monuments dedicated to mass destruction. A multitude of weapons, from rapid-fire machine guns to high-tech lasers are at your disposal as you sweat blood, fighting past 3-D mazes, underground security systems, and tropical forests surrounded by giant waterfalls and alien cannons. This is the ultimate test for the ultimate guerilla warrior. And if you survive, Earth survives!

This game isn't that hard, certainly not enought to merit a warning, especially on a system that has Metal Gear, Ghosts and Goblins, Bayou Billy, and loads of freakish shooters. Save the code for Bayou Billy.

Contra is one of the best games ever made hands down. You play as super tough macho dude Bill Rizer(or Lance Bean if you're player 2), and proceed to rush though an island fortress destroying everything that moves. All while avoiding bullets, laser boulders and aliens.
The game can be tough at first if you're new to the whole run 'n gun thing, but each death makes you a little better and soon you'll be considering yourself a hero.

This game was quite popular when it was first released. Especially since it had quite a hard storyline. Most players did not make it very far without help.
Luckily, Konami had a built in code in the game known as the "Konami Code" Which is "Up, Up, Down, Down, Left, Right, Left, Right, B, A, Start" This code gave the players 30 lives to start with, instead of the usual 3.
 
Download and try this, but be warned, it's extremely hard!