You might remember a while back we wrote a piece about minimalist super-tough reaction-testing games. Things like Super Hexagon and Pivvot.
Well, there's a new kid on the block. It's developed by Kumobius, who also built Time Surfer, and it's just as mean as all the other super-tough reaction-testing kids.
It's called Duet, and it's about a red blob and a blue blob making it through a series of white shapes.
You hold your thumb on the left side of the screen to rotate the conjoined blobs one way. You hold your thumb on the right of the screen to rotate them the other.
Whereas most games start off gently and steadily get tougher, Duet starts cruelly and ends up punching you over and over in the face.
There are 50 levels to work your way through here, each of which lasts no more than a couple of seconds. At least, they don't last that long when you complete them. Add up all your tries and you're looking at hours.
Then, there's an endless mode, in which randomly generated terrain is thrown at you. Each death is marked by a splatter of colour on the obstacle into which you crashed.
If you like your iOS games to make you scream with anguish and roar with triumph, you could do a lot worse than pick up Duet from the App Store for £2.99 / $4.99.