I went in not expecting much; a poor man's Shinobi perhaps, but you should probably lower your expectations even more before going in. The cost is not much, but there are free games of Newgrounds that feel more polished. I did 100% achievements to finish the game, but Area 5 was the only interesting one since getting all the kimonos was challenging in those stages. Let's break it down a bit further:
Gameplay: I was playing on a controller, so I don't know if it is any tighter on keyboard, but jumping can be a bit of an issue. Not the act itself, but while running if you time out to jump near the edge of a platform, most of the time you will not jump leading to a fall. This is particularly frustrating in the last act. The sticking to walls like a magnet to make wall jumping easier can make certain areas more annoying but since it's not that dissimilar from the original Ninja Gaiden you get used to it. There may as well have only been the one ninjutsu since the other 2 are fairly useless. Overall it lacks polish, but the technical aspects are not the biggest problem.
Graphics: 16-bit era graphics are nothing to write home about, but it feels like sprites were imported from RPGmaker. There is nothing anime about this, so no idea where that tag came from. Don't expect cutscenes, the intro and ending are simply the same graphics as the rest of the game. Boring.
Sound: Nothing special, but I guess it works.
Design & Challenge: As noted in graphics the design seems boring and lazy. There are 4 types of enemies throughout the whole game other than bosses: ninja, kunai ninja, dog, monk. They all take 3 hits. This never changes throughout the game and is the laziest and most egregious issue I had I think. As far as challenge, the only parts that felt interesting were in act 5, and only because I was going for the kimonos to 100% - without that it is extremely simple.
Fun: I can say the game entertained me while I was playing it, but I don't think I can say it was actually fun. If it had been more like act 5 throughout, and the jumping were fixed I might have enjoyed it more, but the sameness throughout is a huge detractor. Oh well.