Sega has quite clearly found an emulator that they like to bring their old Genesis games to the iPhone and consequently we're getting rather regular releases of old Genesis titles. One of the latest of these is Shinobi III: Return of the Ninja Master, and while the game is still an enjoyable retro experience, it does serve to highlight a serious flaw or two in the way these games are being brought to the iOS.
A side-scrolling action title, Shinobi III finds our here, Joe Musashi, rather distraught (as distraught as anyone can be in 16-bit and without any major explanation of the story as it opens or progresses) to find out that his enemy, the Neo Zeed, and their leader, Shadow Master, have returned. As you may expect, being an honorable ninja, Musashi—the Shinobi—goes off to save the world once more.
Although that can be a daunting task, Musashi handles it all with just three simple buttons at the your disposal. The first makes him jump; the second has him attack by firing shuriken from a distance and using a sword, punches, and kicks when up close; and the third is the ninja magic button. These ninja magic attacks are incredibly powerful but you're severely limited in how often you can use them (you're given one per stage). The game does build upon these controls, allowing for double jumps and giving out power-ups, but on the whole it's a pretty straightforward setup.
As you progress through the title you'll take on regular old ninjas and a whole bunch of weird, super-powered guys too--it's definitely not your traditional, ninja-only, ninja game. Far more traditional is the level organization, where, more or less, you'll grow through a level fighting basic characters until you reach the end when you take on a boss.
Shinobi III has the exact sort of touchiness to the controls and requires the exact sort of perfect timing one would expect of a classic side-scroller. There aren't a ton of enemies that come at you, but there are enough, and you need to be ready within a split-second to fire a shuriken so as to not get hurt and rundown your life. While running around on horseback, the game is nice enough to give you a warning when you're about to have to vault a barrier, but the timing can still be exceedingly difficult to get down perfectly.