Diorama Battle of NINJA is an action game (Shooter, I guess) by X-Stream Digital, released in 2016. Each level takes place on the same map, following straight on from the previous one by spawning more enemies in after a short delay. There are lots and lots and lots of enemies, and you can run (really really fast, if you want) over everything.

I'm not quite sure how the title works, it also has 虚拟3D世界 忍者之战 on Steam. Not sure if that's a subtitle, or—

• Pickups for items glow the same colour as their UI icon (which also matches their button on an XBox 360 controller.
• Katon (fire attack) is really strong against groups, and the main thing I use against the last boss.
• Fuda (landmine) isn't great as it only hits a few guys at once, but you can place them as you run away from groups. I guess if you really know the stage layouts you could have fun with them.
• Hanabi (homing attack) is very useful against tougher enemies, especially the tengu and others who move fast. Also handy against tightly packed groups, as it can hits lots when they're close together, just not ad many as Katon. Because of the homing element it's useful when running away.

NB: I tried taking screenshots of the credits, but they turned out illegible

• Diorama Battle of NINJA on Steam.