Zanzo

A pointer sweeps a ring. A target sits somewhere on it. Tap as the pointer crosses the target, and it reverses; miss, and the run is over. That is the whole game, and after the first minute it is entirely about your hands.
Every hit makes the sweep faster, until it reaches the fastest a tap can still honestly be timed against. What happens after that is what separates the three modes.

CLASSIC — fifty targets and it ends. The one mode with a finish line, and the only one you can finish.

ENDLESS — no finish line. Past the speed limit the pointer stops accelerating and the target starts closing instead, so the ring keeps asking for more without ever becoming unfair.

NIGHTMARE — everything at once, and early. The target begins shrinking from the first point, it is placed closer, and the ring itself turns, which is what breaks the muscle memory the other modes build. The sequence is fixed, so nightmare is a route: two runs are comparable, and knowing the route is a skill. Afterimages trail the pointer and interference washes down the screen, so seeing it clearly is part of the difficulty.