Like all Sean O’Connor games, this is an excellent game, collects NO PERSONAL DATA of any kind (huge endorsement in my book), and has a couple aspects that will infuriate you.
The Samurai popping his head up can occasionally hide the correct answer, which makes a big difference at the higher levels, when you have like 3 seconds to respond. Certain challenges, like pulling apart the monkeys, also just wrap your thumbs up with near constant movement, making it very hard to do the other two challenges.
Overall, great game and an excellent tool for building selective attention, focus and reflexes!