Ninja Gaiden Trilogy (忍者龍剣伝 巴 Ninja Ryūkenden Tomoe) is a 1995 SNES collection featuring all three [original Ninja Gaiden] games. Few improvements were made, but passwords were included and the cinematic sequences were improved. The graphics were retouched and the soundtrack was updated. The third game was also made more playable by reverting the difficulty level to that of the Japanese version, with infinite continues and more reasonable damage from enemy attacks. Unfortunately, the ports suffered from slowdown, unresponsive controls and no closing credits. Some graphical changes were made that removed parallax scrolling from the backgrounds of the levels. Other graphical changes were made to comply with Nintendo's "Family Friendly" censorship policy at the time (i.e. a pool of blood changed from red to green, and the removal of pentagrams)...
Source: Wikipedia, "Ninja Gaiden", available under the CC-BY-SA License.