From the creator of Ninja Gaiden in Hell https://www.romhacking.net/hacks/2720/ here comes Deadpool Hardcore Edition, an modified version of the hack Deadpool https://www.romhacking.net/hacks/4723/
This version is tougher than the previous one but is also more rewarding by letting you play with 5 characters (instead of only 1) one of them being the original protagonist Ryu Hayabusa. Levels are slightly changed to fit the new difficulty also there are some new graphics here and there and new enemies. Bosses are ruthless, the layout of the levels is changed so they can get the upper hand. Merc mode is recommended in this hack, try hell mode only if you are a veteran of ninja gaiden and already finished Ninja Gaiden in Hell, (this hack is not as broken as NG in Hell but is still very hard)
*Update
Changed a bit the flinch mechanics, enemies speed, modified most of the levels and even added a new complete level plus a new secret image in the bonus level.
Database match: Ninja Gaiden (USA)
Database: No-Intro: Nintendo Entertainment System (v. 20180803-121122)
File SHA-1: CA513F841D75EFEB33BB8099FB02BEEB39F6BB9C
File CRC32: 11F953F6
ROM SHA-1: 15F245161179AB1959B7DC20E82ADD024D23AA3D
ROM CRC32: 7C4A72D8