Disk Rush is a reaction and accuracy test: coloured disks arrive one after another and you tap the side of the screen matching each one's colour. Get it right and it's sorted; get it wrong and the run ends.
The disks arrive faster as you go, so the game becomes about maintaining accuracy while the window shrinks — which is much harder than it sounds after the first thirty seconds.
Rhythm rather than reaction. Settling into a steady tapping tempo and reading only the next disk's colour is more reliable than trying to look ahead at the queue.
Yes — accuracy matters more than speed, which is what makes the accelerating pace so punishing.
Yes — tap the sides of the screen. Nothing to install.