You are a demon slayer. There are 30 levels filled with demons, or at least people that want you dead. Enemies come from both sides, either on the ground or in the air. The level doesn't end until they're all dead. This game is very straightforward, clear the level of enemies. Every few levels is a boss battle. Use the gold you earn to upgrade or purchase weapons. The problem with this is that the game is too repetitive; sometimes a game can do the same thing over and over and still find ways to hold your attention, but there is none of that here. Boss fights for some reason become increasingly hard quite early on. You can avoid taking damage by repeating the same jumping over at the right time, but hitting the boss does almost nothing so it's really drawn out.
The visuals are good and the animation is smooth; now if only they didn't take up so much of the screen! The characters are so close up that you don't see much of the gaming area, and when you're moving back and forth in an area that isn't that big to begin with, it just seems strange.
The in app purchasing hurts this game the most. I found early on that the bosses aren't about using your skills but repetition as they take forever to kill. You can earn gold by killing enemies, but it isn't enough to buy anything on display. Gold is purchasable but I wouldn't recommend spending it here.
Samurai and Ninja looks good, but even so it shows too little when zooming in. The combat is repetitive and the difficulty seems to push the player into spending money on in app currency. If this game had more variety instead only whether you need to kill someone on the ground or in the air, or different kinds of levels, then it might have been alright. But Samurai and Ninja isn't enjoyable and makes too much of a grab for extra cash for me to recommend it.