Cool puzzle and very fun to solve, only thing is it's a bit catchy, sometimes that's just because of the actual nature of the puzzle but other times I think it's the piece design itself. Not the most robust puzzle as there aren't any torpedoes, meaning that it can break easily if dropped and pops a bit-along those lines I'd recommend the qiyi because its torpedoes mitigate all these problems. Would still recommend this for the price but if you have the money, be a tad more indulgent and get the qiyi, it's more worthwhile