The original Shinobi, released on the Sega System-16 board, is a pretty straightforward arcade affair, putting you into the shoes of ace ninja Joe Musashi (who, lacking a cool mask, doesn't look as cool as the iconic title screen suggests). The goal of each level is to find all of the kidnapped children and escape to the end of the stage, although they're never hidden and finding them is pretty easy. The basic gameplay borrows heavily from Namco's Rolling Thunder games, mixing strategic gameplay with fast action. Like Rolling Thunder, you jump between planes by holding up or down and hitting jump. Joe can leap between rooftops, or behind fences, in dual plane level designs that were pretty unique for 1987.
Of course, the relentless stream of bad guys makes the trek difficult—some of them mindlessly charge at you, but others hide behind boxes or block your attacks with shields. Even more deadly are the ninjas, who appear out of nowhere in large numbers and will surround Joe if they're not dealt with quickly. Sure, you'll be hammering that fire button to toss out as many shurikens as possible, but you'll also have to properly time your assault, hopping on enemies while they've dropped their defenses. While your primary weapons are throwing shurikens, getting close to an enemy and attacking will unleash a melee attack - either a karate punch or a sword slash, depending on your power-up - that will usually break through their defenses. Joe's a fragile ninja, and one bullet or stab wound will kill him, sending him back to the beginning the level, but he can still ram into enemies as long as no weapons touch him. This is actually one of the finer strategies of the game, as it allows to stun the enemies and deliver a quick killing blow.
There are plenty of memorable boss battles too—each one will usually make an appearance in the stages to taunt you or get off a few quick shots. Each are introcued with a document prefacing each level, showing the route of your attack, and stamping their portrait when they are killed. The first is a hulking armor clad warrior named Ken-Oh, who tosses fireballs from his fists and can only be damaged with a shuriken right in the face. The second is Black Turtle, an entire helicopter, which sends a never-ending flood of soldiers out of its bay doors until you, a mere human ninja, can take it down. The third level is a strange mechanical face called Madara, which is attached to the wall and shoots bounding fireballs from its mouth, and is guarded by a series of rotating statues that slowly creep forward and try to crush you against the wall. The fourth boss, Lobster, is a large sword-wielding samurai that, again, can only be attacked in the head, while the fifth and final enemy, the Masked Ninja known as Nakahara who is also Joe's former mentor, wields the power of lighning.
The game can get tough, but you get ninja magic to use once each level, which clears the screen of enemies or does some cheap and easy damage to bosses. There are bonus stages, first person shooting galleries that are extremely tough but reward the skillful ninja with extra lives. Overall, Shinobi is still a damn fine game, a true classic that's aged very well.
The first home port of Shinobi was the Sega Master System version. While significantly slower paced than the arcade game, it still maintains the methodical feel of the gameplay, and is still excellent. There are noticeable additions too, including a lifebar and several new weapons you get for rescuing hostages, including guns, whips and bombs. Rescuing the hostages is also no longer mandatory, although given the power-ups, is a worthwhile thing to do. However, the importance of ninja magic is downplayed, as you only get to use them after beating one of the incredibly difficult bonus stages. Much of the music is gone and replaced with a single tune, but the huge bosses still remain, although they don't taunt you during the stages anymore. Regardless of being a very different game, it's still one of the Sega Master System's better action titles, even if they cut the ending, so upon beating Nakahara, you get the same "Game Over" as you would if you'd run out of lives. Tengen's Nintendo Entertainment System port is based on the Sega Master System game, although it suffers from terrible graphics and shaky gameplay, like all of their conversions. The additional close ranged weapons are gone, the vertically scrolling stages have been redesigned into horizontal stages, and Joe can only toss a single projectile at a time. The ninja on the title screen is also amusingly cross-eyed.
The PC Engine version, converted by Asmik, is closer to the arcade game, with decent (if somewhat darker) graphics and similar gameplay. However, all of the close-up melee attacks are gone, severely altering the way the game is played. It's also missing the second stage from the original, and the bonus levels are gone.
There are also a couple of home computer versions, mostly for European markets. Amiga and Atari ST deliver the most faithful ports, which only differ from the arcade version in resolution, colors and HUD, as well as some minorly different mechanics. Since most of these computers only support 1-button joysticks, Joe now jumps by pressing up, while holding the attack button and tapping either up or down switches between the planes. All the 8-bit computers have to live with more compromises: the graphics are redrawn for all, and they lose the boss title cards that used to be shown before each stage. Because of the not so smooth controls, they're also a bit harder than the original. The C64 also loses the music, as well as some Spider-Man look-a-like enemies in the second level. Same goes for the IBM-PC version, which kinda seems to be based off the C64 one, but is a rather shoddy port altogether, with terrible controls and broken enemy patterns. The laziest is the MSX "port" though, which is just a conversion from the Spectrum with the same yellow-dominated 4-color graphics. The title screen for that version, with one guy punching another guy in the face, is at least amusing.
The only other nearly-perfect ports of Shinobi are found as an unlockable on Sonic's Ultimate Genesis Collection for the PlayStation 3 and Xbox 360, or as a separate download on the Xbox Live Arcade. The latter version has the Marilyn Monroe pictures that used to decorate one stage removed, and the Spider-Man enemy is now painted green.
Shinobi for mobile phones appeared in China, dubbed Guiying Renzhe (鬼影忍者) Shinobi, "Ghost Ninja Shinobi." Western sources refer to it as "Shinobi Tolerance." This is a complete remake rather than a port, with entirely new graphics (The hero now looks like Hotsuma from the PS2 game and rescues hot ninja chicks) and a second character to unlock. Joe (or Hotsuma?) also gets a health bar with three hit points and three different ninja spells. This is no doubt the best looking version of the game, but the controls are platform-typical quite terrible. Planes are switched by holding up (which is also jump) or down (duck) for a while, probably for that reason every movment has a very annoying delay. You can save the game after each level, but it keep track of extra lives and score, too, so it cannot be exploited. At least you're not forced to always start from the first stage. The Marilyn Monroe pictures are gone here as well, and the Spider-Men are turned into goo-ninjas similar to the ones in The GG Shinobi II.