I'm not sure what your personal ninja journey might be, but I was introduced to the charms of Joe Musashi via the 1988 Master System port of Shinobi rather than the original arcade version, which was released a year earlier.
This home conversion was not a straight port of the coin-op – that might sound obvious given that the Master System wasn't capable of matching the arcade Shinobi's visuals, but there were considerable gameplay changes, too.
One-hit kills were replaced with a health gauge, while the rescuing of hostages was entirely optional. The home version also 'feels' very different to its big brother – not that I minded back in the late '80s, of course, as I had nothing to compare it against.
Fast-forward to the present day, and hacker Kuato has published a new patch which aims to give the Master System port a boost while keeping its unique gameplay features intact.
Shinobi – The Real Ninja is an enhancement hack that includes three different gameplay versions. 'Classic' adds a hood to Musashi's head and increases the number of projectiles on-screen at any one time. 'Arcade' includes the additions from 'Classic' but also adds in rapid fire for all weapons and faster melee attack speed. Also, the durability of Mandara boss statues is increased by a single hit.
Finally, we have 'Enhanced' mode, which includes all previous changes, reduces Musashi's jump height, and adds a double jump.
You'll need to apply the patch to either the North American or European ROM of the game.