3 stars: Good game, but needs balancing. Progress slows to a crawl the higher your shuriken get. Assuming an auto merge every 5 seconds with a rapid upgrade chance of 50% (which is very generous because you need thousands of rubies to even get to that) it would take more than six months of constant playing to get to the highest shuriken. Some of the upgrades are also way overpriced, which further slows mid- to endgame progress. Additionally the gold rewards from regular monsters could use a buff, compared to the boss gold rewards they're simply not with the time. Bottom line: this is a solid game and I had fun playing it, but the mid- to endgame need some serious rebalancing.
3 stars: Fun game, but it gets really slow after the 3rd boss. Also the 1000 gem upgrade for 200% was awesome, however I am strongly against the 1000 gem upgrade for 1% increase in double upgrade chance. It's the same thing as the another upgrade except more expensive. It's also a lot less worth the price than the 200% damage. I was expeciting the 1000 gems to get me at least 25% double upgrade chance. I am personally a fan of how this game does not have resets or rebirths, however perhaps there could be some other content unlocked at later stages to keep me playing more as the game slows down.
4 stars: I really wish that it didn't drain my battery life to 0% so quickly with my phone that lasts 3-6 days. I also wish that somehow you could upgrade your starting shurikens so you didn't have t...