I have completed both NG Ragebound and Shinobi Art of Vengeance. While both of these games are 2d action games, they're quite different for each other.
Ragebound goes for more of the traditional side scroller stage based formula, once the mechanics are fully introduced after a few levels, the rest of the game comes down to player execution. There are some items to earn and equip to vary up the one's play style somewhat, but the difference in loadout isn't that substantial, that it's really gonna change much compared to how you are early on. The one item that makes the biggest difference would be the one that increases your damage when at low health, as with the bosses being pretty challenging with fairly large health bars, that damage boost is pretty appealing.
When it comes to Shinobi it is for the most part the standard MetroidVania, There are still multiple stages, but they all have that layout where you will earn exploration abilities later and return to prior areas and find more stuff. This game goes far more into the player growing stronger as it goes on. There are many abilities to buy to increase your combo variety, upgrade health and such, and the equipables play a more significant role, as with the right ones you can really trivialize some of the Difficulty, after beating the main game you'll unlock an arcade mode which you can get S ranks for, and they're probably the most challenging part since the simplest method of getting an S rank is no damaging the level. but this would require a no hit run for around 10-15 mins of level. There is one equipable which increases your damage as your combo count gets higher, and your combo doesn't reset unless you take damage, you can pair that with a second equipable so that you get a shield which will guard you for 1 hit, and it takes a full minute to recharge, this is pretty much the pair to use for getting S ranks. playing the normal game without that goal for S ranks, it's nothing too challenging, but still entertaining. The combat can be a bit button mashy, but it stays satisfying though out the full game,. It's actually the platforming where most of the games challenge comes from. Plenty of the optional areas task you with real platforming that put your movement to proper use, and the movement feels good enough that it all enjoyable, the game in general feels good to play.
Out of the two games, Ragebound is probably the more favorable of the two in terms of the full package it's a tighter more focused experience, where while Shinobi is good, aside from the art of the levels being high quality, it's a bit Generic in it's other areas. The story being it's weakest aspect. In NG Ragebound Kenji and Kumori as leads are plenty likeable characters, so the blandness of Shinobi's characters sticks out in comparison. Joe Musashi is a silent character though out the game, and the story might have been improved if every character was also silent, and the story was simply shown though what you saw on screen and though the art.